Full text of "Gasoline automobiles ; Gasoline automobile engines ; Automobile engine auxiliaries ; Electric ignition ; Transmission and control mechanism ; Bearings and lubrication ; Automobile tires"

See other formats

This is a digital copy of a book that was preserved for generations on library shelves before it was carefully scanned by Google as part of a project
to make the world's books discoverable online.

It has survived long enough for the copyright to expire and the book to enter the public domain. A public domain book is one that was never subject
to copyright or whose legal copyright term has expired. Whether a book is in the public domain may vary country to country. Public domain books
are our gateways to the past, representing a wealth of history, culture and knowledge that's often difficult to discover.

Marks, notations and other marginalia present in the original volume will appear in this file - a reminder of this book's long journey from the
publisher to a library and finally to you.

Usage guidelines

Google is proud to partner with libraries to digitize public domain materials and make them widely accessible. Public domain books belong to the
public and we are merely their custodians. Nevertheless, this work is expensive, so in order to keep providing this resource, we have taken steps to
prevent abuse by commercial parties, including placing technical restrictions on automated querying.

We also ask that you:

+ Make non-commercial use of the files We designed Google Book Search for use by individuals, and we request that you use these files for
personal, non-commercial purposes.

+ Refrain from automated querying Do not send automated queries of any sort to Google's system: If you are conducting research on machine
translation, optical character recognition or other areas where access to a large amount of text is helpful, please contact us. We encourage the
use of public domain materials for these purposes and may be able to help.

+ Maintain attribution The Google "watermark" you see on each file is essential for informing people about this project and helping them find
additional materials through Google Book Search. Please do not remove it.

+ Keep it legal Whatever your use, remember that you are responsible for ensuring that what you are doing is legal. Do not assume that just
because we believe a book is in the public domain for users in the United States, that the work is also in the public domain for users in other
countries. Whether a book is still in copyright varies from country to country, and we can't offer guidance on whether any specific use of
any specific book is allowed. Please do not assume that a book's appearance in Google Book Search means it can be used in any manner
anywhere in the world. Copyright infringement liability can be quite severe.

About Google Book Search

Google's mission is to organize the world's information and to make it universally accessible and useful. Google Book Search helps readers
discover the world's books while helping authors and publishers reach new audiences. You can search through the full text of this book on the web

at http : //books . google . com/|

Digitized by

Google

Digitized by

Google

Digitized by VjOOQ IC

Digitized by

Google

Digitized by

Google

K.F. WENDT LIBRARY
UW COLLEGE OF ENGR.

21 sjaBgggwENUE

rc5

Digitized by

Google

Digitized by

Google

Digitized by

Google

Digitized by

Google

Digitized by

Google

Digitized by

Google

Digitized by

Google

INTERNATIONAL
LIBRARY OF TECHNOLOGY

A SERIES OF TEXTBCX)KS FOR PERSONS ENGAGED IN THE ENGINEERING

PROFESSIONS AND TRADES OR FOR THOSE WHO DESIRE

INFORMATION CONCERNING THEM. ' FULLY ILLUSTRATED

AND CONTAINING NUMEROUS PRACTICAL

EXAMPLES AND THEIR SOLUTIONS

GASOLINE AUTOMOBILES

GASOLINE AUTOMOBILE ENGINES

AUTOMOBILE ENGINE AUXILIARIES

ELECTRIC IGNITION

TRANSMISSION AND CONTROL MECHANISM

BEARINGS AND LUBRICATION

AUTOMOBILE TIRES

(VOU 0

SCRANTON
INTERNATIONAL TEXTBOOK COMPANY

HOB

Digitized by

Google

Gasoline Automobiles: Cop3rright, 1913, by International Textbook Company. Copy-
right in Great Britain.

Gasoline Automobile Engines: Copyright, 1913, by International Textbook Com-
pany. Copyright in Great Britain.

Automobile Engine Auxiliaries: Copyright. 1913. by International Textbook Com-
pany. Copyright in Great Britain.

Electric Ignition, Parts 1 and 3: Copyrifi^t, 1907. 1910, by International Textbook
Company. Entered at Stationers' Hall, London.

Electric Ignition, Part 2: Copyright, 1910, by International Textbook Company.
Entered at Stationers' Hall, London.

Electric Ignition. Part 4: Copyright. 1913. by International Textbook Company.
Copyright in Great Britain.

Transmission and Control Mechanism: Copyright, 1914. by International Textbook
Company. Copyright in Great Britain.

Bearings and Lubrication. Part 1: Copyright. 1913. by International Textbook Com-
pany. Copyright in Great Britain.

Bearings and Lubrication, Part 2: Copyright. 1914, by International Textbook Com-
pany. Copyright in Great Britain.

Automobile Tires: Copyright. 1914. by International Textbook Company. Copy-
right in Great Britain.

Press OF
International Textbook Company

. SCRANTON, Pa.

29581
HOB

Digitized by

Google

^02330

APR -6 I9!B
SB

HOB

PREFACE

The volumes of the International Library of Technology are
made up of Instruction Papers, or Sections, comprising the
various courses of instruction for students of the Interna-
tional Correspondence Schools. The original manuscript for
each Instruction Paper is prepared by a person thoroughly
qualified, both technically and by experience, to write with
authority on his subject. In many cases the writer is regularly
employed elsewhere in practical work and writes for us during
spare time. The manuscripts are then carefully edited to make
them suitable for correspondence work.

The only qualification for enrolment as a student in these
Schools is the ability to read English and to write intelligibly
the answers to the Examination Questions. Hence^ our stu-
dents are of all grades of education, and our Instruction
Papers are, therefore, written in the simplest possible lan-
guage so as to make them readily understood by all students.
If technical expressions are essential to a thorough under-
standing of the subject, they are clearly explained when first
introduced.

The great majority of our students wish to prepare them-
selves for advancement in their vocations or to qualify for
other and more congenial occupations. Their time for study
is usually after the day's work is done and is limited to a few
hours each day. Therefore, every effort is made to give them
practical and accurate information in clear, concise form, and
to make this information include all of the essentials but none
of the non-essentials. To effect this result derivations of rules
and formulas are usually omitted, but thorough and complete
instructions are given regarding how, when, and under what

Digitized by

Google

iv PREFACE

conditions any particular rule, formula, or process should be
applied. Whenever possible one or more examples, such as
would be likely to arise in actual practice, together with their
solutions, are given for illustration.

As the best way to make a statement, explanation, or descrip-
tion clear is to give a picture or a diagram in connection with
it, illustrations are very freely used. These illustrations are
especially made by our own Illustrating Department in order
to adapt them fully to the requirements of the text. Projec-
tion drawings, sectional drawings, outline drawings, perspec-
tive drawings, partly shaded or full shaded, are employed,
according to which will best produce the desired result. Half-
tone engravings are used only in those cases where the general
effect is desired rather than the actual details.

In the table of contents that immediately follows are given
the titles of the Sections included in this volume, and under
each title is listed the main topics discussed. At the end of
the volume will be found a complete index, «o that quick
reference can be made to any subject treated.

International Textbook Company

iicm

Digitized by

Google

CONTENTS

Gasoline Automobiles

General Characteristics

General Assembly of the Automobile .
Methods of Propelling the Automobile

Bodies and Accessories

Types of Bodies

Accessory Fittings

Automobile Tops

Wind Shields

Speedometers

Automobile Rimning Gear

Wheels

Front Axles

Rear Axles and Housings

Springs and Frames

Shock Absorbers

Section

Gasoline Automobile Engines

Principles of Operation 2

Four-Cycle Principle 2

Two-Cycle Principle 2

Typical Automobile Engines 2

Four-Cycle Engines 2

Unit Power Plant ! 2

Two-Cycle Engines 2

Details of Construction 3

Automobile-Engine Cylinders 3

Crank-Cases 3

Manifolds 3

Reciprocating and Rotating Parts 3

Page

102

1
1

13
18
18
42
46
1
1

15
24
27

Digitized by

Google

vi CONTENTS

Gasoline Automobile Engines — (Continued) Section Page

Valves and Valve Mechanism 3 37

Engine Fittings and Engine Rating .... 3 48

Automobile-Engine Auxiliaries

Cooling, Muffling, and Governing ..... 4 1

Water Cooling 4 2

Air Cooling 4 27

Exhaust Mufflers 4 30

Governing Devices 4 34

Electric Ignition

Theory and Application 6 1

Electrodynamics 6 4

Magnets and Magnetism . . 6 12

Electromagnetic Induction 6 18

Ignition Apparatus 6 20

Primary Batteries 6 22

Secondary, or Storage, Batteries 6 30

Spark Coils 6 41

Induction Coils 6 43

Current-distributing Devices 7 1

Ignitess 7 1

Spark Plugs 7 5

Timers 7 10

Distributors 7 12

Switches 7 21

Current-Measuring Instruments 7 28

Ignition Systems 7 34

Low-Tension Ignition 7 34

High-Tension Ignition 7 36

Dual Ignition 7 45

Direct-Current Generators 8 -1

Principles of Operation 8 1

Details of Construction 8 7

Magneto-Electric Generators 8 19

Details of Construction 8 24

Low-Tension Magnetos 8 29

Low-Tension Magneto-Ignition Systems . . 8 36

Digitized by

Google

CONTENTS vii

Electric Ignition — (Continued) Section Page

Dual Ignition Systems 8 42

High-Tension Magnetos 8 45

Spark Control 8 63

Spark Intensity 8 79

Starting on the Spark 8 89

Modem Ignition Systems 8 91

Single Magneto-Ignition Systems 8 91

Dual Ignition Systems 8 104

Double Ignition Systems 8 117

Miscellaneous Ignition Systems 8 124

Transmission and Control Mechanism

Friction Clutches 9 1

Cone Clutches 9 3

Disk Clutches 9 14

Contracting and Expanding Clutches ... 9 25

Clutch-Operating Devices 9 30

Clutch Brakes 9 34

Friction Material for Clutches 9 35

Transmission Mechanism 9 37

Speed-Changing Mechanism 9 37

Sliding Change-Speed Gears 9 38

Planetary Change-Speed Gears 9 58

Friction-Gear Transmission 9 62

Electric Gear-Shifting Mechanism 9 64

Pnetmiatic Gear-Shifting Mechanism ... 9 70

Two-Speed Bevel-Gear Rear Axle 9 72

Power Transmission Details 9 76

Control Mechanisms 9 86

Steering Mechanisms 9 86

Brake Mechanism 9 97

Bearings and Lubrication

Bearings 10 1

Plain Bearings 10 1

Antifriction Bearings 10 14

Straight Roller Bearings 10 15

Tapered Roller Bearings 10 20

Digitized by

Google

vin CONTENTS

Bearing and Lubrication — {Continued) Section Page

Radial Ball Bearings 10 23

Radial-and-Thrust Ball Bearings 10 35

Ball Thrust Bearings 10 39

Lubrication 10 43

Lubricants 10 43

Engine Lubrication Systems 10 60

Splash Lubrication Systems 10 53

Pressure-Feed Lubrication Systems .... 10 65
Combined Splash and Pressure-Feed Lubri-
cation System 10 73

Lubricating Devices 10 75

Automobile Tires

Tire Construction and Application .... 11 1

Pneumatic Tires 11 1

Demountable and Quick-Detachable Rims .11 9

AirValves, Lugs, and Inner Tubes 11 16

Tire Maintenance 11 24

Inflation of Tires 11 24

Pump Connections and Pressure Gauges . . 11 36 ■

Tire Protectors and Antiskid Devices ... 11 40

Tire Deterioration and Repairs 11 45

Causes of Tire Failure 11 45

Roadside Tire Repairs 11 53

Tire Tools 11 53

Handling of Clincher Tires 11 56

Handling of Quick-Detachable Tires . ... 11 63

Roadside Inner-Tube Repairs 11 65

Roadside Repairs to Casings 11 69

Vulcanized Tire Repairs 11 73

Digitized by

Google

GASOLINE AUTOMOBILES

(PART 1)

GENERAL CHARACTERISTICS

INTRODUCTION

CLASSIFICATION OF MOTpB VEHICLES

1. In its broadest sense, the term automobile applies to any
self-propelled vehicle, including even steam road rollers, the
traction engines used in agricultural work, and locomotives.
Custom, however, has narrowed the application of this term
until it is now chiefly applied to the self-propelled vehicles used
for the transportation, without pa)rment therefor, of passengers
for pleasure or for business pxuposes. When the same auto-
mobile is diverted from its original purpose to the canying of
passengers for a money consideration, it is then spoken of as
a livery automobile or a livery car, implying that it is for hire.
The terms motor car, or car for short, and motor vehicle are used
S3monymously.with the term automobile.

Motor vehicles devoted entirely to the carrying of freight
are called motor trucks, auto trucks, delivery cars, delivery wagons,
or commercial vehicles, the latter term being sufficiently broad
to embrace them all as a class distinct from pleasure vehicles.
Although automobiles are sometimes hired for touring pur-
poses, motor vehicles for the transportation of passengers for
hire in cities are of two general classes, namely, motor busses
and taxicabs. The latter are usually designed to carry four

COrrniCHTBO by INTKIINATIONAt. TKXTBOOK COMPANY. ALL RICHTS RKSKRVKO

§1

222B— a

Digitized by

Google

2 GASOLINE AUTOMOBILES § 1

passengers and considerable baggage as well. They are used
extensively in large cities, where they are very popular for
making short business and pleasure trips. Motor busses are
usually operated on certain main thoroughfares where there
are no street-car Unes. They carry a large ntmiber of pas-
sengers, some inside and some on top of the vehicle, and make
regular trips at stated intervals between specified points,
stopping to take on or to let off passengers at street crossings
whenever signaled to do so. What are known as "sight-
seeing** motor vehicles are automobiles especially designed
for the transportation of a large niunber of passengers on sight-
seeing trips, the places of interest along the selected routes
being pointed out and described by the man in charge of the
vehicle.

At present, most automobiles are driven by internal-com-
bustion engines using gasoline as fuel, the power developed
by the engine being applied to the driving road wheels by means
of suitably arranged power-transmitting mechanism.

GENERAL ASSEMBLY OF THE AUTOMOBILE

2. There are two principal parts to an automobile, namely,
the chassis (pronounced shah-see) and the body. As originally
employed by the French, from whom it has been borrowed,
the term chassis was used to designate only the frame of the
automobile, but as now used it applies to the assembly of the
running gear, consisting of wheels, axles, springs, and frame,
and the power plant, which includes the engine and transmis-
sion. In other words, the chassis includes everything but the
body and its accessories. Before considering in detail the con-
struction of the various parts of the chassis, attention will be
given to the assembled parts of the automobile as a whole, the
names, location, arrangement, purpose, and relations of the
principal parts being noted. In conjimction with this, it should
be noted that while automobiles produced by different manu-
facturers greatly resemble one another in their general features,
. there is naturally a great difference in the design of the details
and the location and arrangement of many parts. For this

Digitized by

Google

Digitized by

Google

4 GASOLINE AUTOMOBILES § 1

reason, some of the details of the description of an automobile
given here apply to only the particular motor car that is illus-
trated, the general features of this automobile, however, being
common to all of the same type.

The various component parts of an automobile are here
treated in a general way, and their construction, functions,
operation, and management are explained in detail in the
proper places.

Fig. 2

3. Three illustrations of a Chalmers "Thirty-six" five-
passenger automobile of the touring-car class are presented
in Figs. 1 to 3. Fig. 1 shows a perspective side view of the
right side of the automobile; Fig. 2, a view of the front com-
partment looking toward the front and the right, the left front
door of the body having been opened wide; and Fig. 3, a per-
spective front view of the automobile. In connection with

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 5

this, it should be noted that the right side of a motor car is
the one at the right of the observer when he is in one of the seats
and is facing toward the front; under the same conditions,
the left side of the motor car is at his left.

The automobile shown is intended to seat two persons in
front and three in the rear; the driver of this car sits at the
right, but in some makes of automobiles the driver sits at the
left.

As far as possible, the same parts are lettered alike in Figs. 1
to 3, and all three illustrations should be referred to in reading
the description.

4. Just in front of the driver's seat a is a steering wheel b
at the top of the inclined steering column c. The guiding of

Fig. 3

the car is accomplished by rotating this wheel through part
of a revolution by hand. This rotation transmits motion to
the front road wheels d, so as to turn them sidewise and change
the direction of travel of the car.

Pedals e, e\ and e", which can be seen only in Fig. 2, pro-
ject through the floor of the front compartment, the board e\
being known as the toe hoard, because it is under the toes of
the driver. For a similar reason, the part e^ of the front-
compartment floor is known as the heel hoard. The clutch

Digitized by

Google

6 GASOLINE AUTOMOBILES § 1

pedal e is used for engaging the engine with the driving
mechanism or disengaging the engine from it. The service"
brake pedal e' is used for applying the brakes ordinarily
employed in regular service to slow down the car or to stop
its travel. The accelerator pedal e*\ often called the jooi-
throttky is used for increasing or decreasing the speed of the
engine. All three pedals are operated by the pressure of the
driver's foot.

At the right side of the car, and just forward of the driver's
seat, are located two levers / and g. One, the emergency-brake
lever f, controls a set of brakes independent of the service brakes,
and is used for applying these brakes in an emergency, either
in conjimction with the service brakes or alone in case the serv-
ice brakes are out of order or it is considered undesirable to
use them. The other lever g, which is called the gear-shift
lever, the change-speed lever, and also the speed-control lever,
is eniployed for adjtisting the power-transmitting mechanism,
so that the speed of travel of the car can be varied through
a greater range than that obtainable in the engine, and also
for giving the car backward travel. This' arrangement is use-
ful and generally necessary in order to obtain both high and
low speeds of travel, and also in order to be able to climb steep
hills. A gasoline engine such as is used on automobiles rotates
in only one direction and cannot be run at very low speeds.
The minimum speed of rotation of automobile engines is prob-
ably never as low as 100 revolutions per minute and generally
not lower than 200, 300, or even more, according to the size
and form of the engine.

On top of the steering wheel b are two small levers 6' and &"
(see Fig. 2) for controlling the power and the speed of the engine.
Each of these levers is attached to a shaft, or tube, that extends
down inside the steering column that supports the steering
wheel. One of the levers is for regulating the amount of fuel
delivered to the engine, and the other is for regulating the
instant at which the fuel is ignited. The lever b' for regula-
ting the supply of fuel is called the throttle lever; the lever &"
for regulating, or varying, the time of ignition is called the
spark lever, or spark control.

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 7

On the right-hand side of the cowl board h, to the top of which
the wind shield i is attadied, there is located a pear-shaped
rubber btdb /. This bulb is connected by means of a flexible
metallic tube f to a signal horn /", Fig. 1, located at the right
side of the car and somewhat above the level of the floor of the
car. The horn is blown by pressing this bulb with the hand.
The purpose of the wind shield, which is hinged near its center
so that it can be folded downwards, is to protect the occupants
of the front seats from the impinging of air against the upper
part of their bodies on accotmt of the forward motion of the car.

5. In the car here illustrated, the engine is arranged to be
started by means of compressed air carried in a storage tank;
the pressure in this tank is indicated on the starter air-pressure
gauge k, Fig. 2, which is mounted on the board A. A push
button k' is mounted on the dashboard /, and upon being pushed
with the hand or the foot it admits compressed air to the engine.
The pedal k'\ when depressed, starts a small air compressor
that ptunps air into the storage tank.

A spark coil m is mounted horizontally on the board h; it
forms part of one of the two systems for igniting the fuel with
which this car is equipped. One end of the spark coil pro-
jects through the board h and carries a switch handle by
means of which the ignition may be switched off entirely, or
either ignition system switched on.

The fuel for the engine of this car consists of a mixture of
the right proportions of gasoline and air. This mixture is
formed in a device called a carbureter , the gasoline being forced
to the carbureter from the gasoline tank by air pressure, which
is kept up automatically while the engine is running by a small
engine-driven air ptmip. A hand air pump n is employed for
pumping up air pressure in the gasoline tank after the tank
has been filled, or when the air pressure in the tank is too low
from any cause to force the gasoline to the carbureter.

6. The Chalmers "Thirty-six" automobile is equipped with
two electric headlights. These, as shown at o. Figs. 1 and 3,
are located at the front end of the car, and serve to light the
road at night. A switch o\ Fig. 2, on the board A, is used

Digitized by

Google

8 GASOLINE AUTOMOBILES § 1

for switching the electric current on or oflE all the lamps; a
measuring instrument o*\ called an ammeter, indicates the
current that is flowing to the lamps. Combination oil-and-
electric lamps p and q are used as signal lights at night to indi-
cate the position of the car to other users of the road; these
lamps can be seen in Figs. 1 and 3. The two lamps p are placed
in front of the dash near its top; they are called side lamps
or side lights, and are arranged to throw a clear white light
ahead, thus indicating to an observer that the car is facing
him. The lamp q, which can be seen only in Fig. 1, is called
the tail-lamp, or tail-light; it is always arranged to show a red
light toward the rear, thus indicating to an observer that he
is looking at the rear of the car. The tail-lamp is also arranged
to throw a white light at right angles to the car for the purpose
of illiuninating the rear license tag in localities where cars
are required by law to carry such tag. The side lamps and
tail-lamp are arranged to use oil in addition to electricity
as a precautionary measure, the oil burners being lighted when
electric current for any reason is not available. While the
engine is running, the electric current for lighting the lamps
is furnished by means of a small current generator, called a
dynamo, which is driven by the engine; when the engine is
stopped, the electric current is furnished by a storage battery.

7. A radiator r, Figs. 1 and 3, is mounted at the extreme
front of the car; its purpose is to cool the water used for keep-
ing the engine cylinders from becoming too hot.

The engine, which cannot be seen in any of the illustrations,
is located in the front of the car, between the radiator and the
dash and underneath the hood s, Fig. 1; beneath the engine
is placed a mud-pan, or sod pan, t, which protects it from mud
and dust. At the extreme front of the car is a crank-handle,
or starting crank, u, Fig. 3, which is used for starting the engine
if the compressed-air starter for any reason fails to start it.

An oil sight-feed glass v. Fig. 2, is placed on the dash to show
whether or not the oil pump that lubricates the engine is work-
ing properly; a carbureter adjustment w is also carried on the
dash. A speedometer x indicates the speed of the car in miles

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 9

per hour. A valve operated by the handle i'" shuts off com-
munication between the air tank and the starting button.

The body of the car, consisting of the front and rear seats,
together with the necessary doors to give access to the seats,
is moimted on the frame of the car; it is fitted with a folding
top y, shown folded in Fig. 1 and covered by a slip top cover y\

The car is driven by the rear wheels d\ which are rotated by
the engine. Mud-guards, or fenders, d'' are placed over all the
wheels to prevent mud from splashing over the occupants
of the car; the front and rear fenders are connected to running
boards du which serve as steps to facilitate entering and leaving
the front and rear compartments of the body. Springs are
interposed between thefratne z of the car and the axles on which
the road wheels are mounted, in order that the occupants may
ride over the road in comfort.

METHODS OF PROPELLING THE AUTOMOBILE

DEFINITIONS

8. An automobile is propelled by rotating either all four
wheels, or only the rear wheels, or only the front wheels, by
some suitable mechanism driven, in tiun, by the engine. The
method of driving all four wheels simultaneously has been,
and still is, used to a sli^t extent on one make of motor truck,
but it is not employed on any regularly built pleasure cars.
Propelling an automobile through its front wheels has been
tried out successfully, but no cars embodying this feature are
r^ularly in the market. Practically all automobiles are
propelled by rotating their rear wheels.

Power may be transmitted to the rear wheels (1) by chains
and sprockets, thus making the car chainrdriven; (2) by means
of a rotating shaft and either bevel gearing or worm-gearing,
thus making the car shaft-driven; (3) by friction gearing, thus
making it frictionrdriven; (4) by a combination of friction gear-
ing and chain and sprocket, thus making it friction-and-chain
driven.

Digitized by

Google

Digitized by

Google

Digitized by

Google

12 GASOLINE AUTOMOBILES § 1

Chain-driven cars may have both rear wheels driven by a
single chain, which is usually located near the center of the
rear axle. In such a case, the wheels are driven by shafts
rotated by means of the chain, the shafts being inside the rear
axle, which is then known as a live axle, and the car is spoken
of as a single-chaifirdrive car. Pleasure cars employing this
method of propulsion, however, are practically obsolete. Each
rear wheel may be driven by its own chain, in which case no
part of the rear axle revolves. Such an axle is spoken of as a
dead rear axle, and a car thus driven is said to have a double-
chain drive, or, since the chains are naturally located at the
sides of the car, it is often spoken of as a side-chain-drive car.
Although the double-chain drive is very common in motor
trucks, it is employed but very little in pleasure cars at present.

Most of the automobiles in use in the United States and
Canada employ a live axle and are shaft-driven.

NOMENCLATURE OF TYPICAL CHAfiU9L9 PARTS

9. Two views of the chassis of a Studebaker **20*' shaft-
driven automobile are shown in Figs. 4 and 5, on which the
same parts have the same reference figures. Fig. 4 is a plan
view, the steering column being broken off so that the steering
wheel and throttle and spark levers thereon will not hide the
toot-levers, or pedals, and Fig. 5 is a side elevation partly in
section. Beginning at the front end of the chassis the various
parts are numbered and named as follows:

i, Front road wheels 8, Arms of steering knuckles

S, Front axle 9, Steering rod or drag link, one

S, Front springs, of the semielliptic end of which is attached to

type arm 8 of left steering knuckle,

4, Front end of frame, forming the other end of the steering

hanger for front spring rod being connected to the

5, Side members of frame actuating lever arm of the

6, Starting crank for starting steering gear

engine 10, Radiator in which water for dr-

7, Tie-rod, distance rod, or cross- culation in engine water-

connecting rod with adjust- jackets is cooled

able end joining arms of 11, Fan to create circulation of air

steering knuckles or pivots through radiator, thus cooling

Digitized by

Google

§1

GASOLINE AUTOMOBILES

water therein when car is S7,
standing still while engine is B8,
in operation, and aiding dr- £9,
dilation while car is running
IS, Cross-member of frame SO,

13, Gear-driven pump for drcula- SI,

ting cooling water
i4t Water-delivery pipe from pump

to cylinder water-jackets ; also SB,
called water-inlet pipe and
pump-outlet pipe SS,

15, Water-outlet pipe conveying

water from cylinder water- Si^,
jackets to radiator S6,

16, Large fan-belt pulley on end of

engine cam-shaft S6,

17, Small flanged fan-belt puUey

18, Bracket for supporting spindle

on which small fan-belt pulley
and fan rotate

19, Cylinder casting comprising S7,

four cylinders, which are cast S8,
as a monobloc; that is, com-
bined into a single casting S9,

fSO, Water-jacket surroimding upper 40,
part of cylinder and cast in- 4/,
t^;ral with it

£1, Cylinder cover closing upper
water-jacket opening

££, Plugs closing openings above

the eight valves, which are 4^,
put in place or removed 4S,
through the openings; the
spark plugs (not shown) are
placed in the valve plugs over 44t
the four intake valves; pri- 4^,
ming cocks (not shown) are 4^,
fitted to the valve plugs over
the four exhaust valves

£3, Exhaust pipe manifold 4^»

£4, Muffler ^,

£S, Intake openings of cylinders, to

which intake manifold is fitted 4^,

26, Exhatist openings of cylinders,
to which exhaust manifold is
fitted 50,

Dash

Steering column

Steering-gear-case cov«r at
lower end of steering column

Steering wheel

Quadrant on which are mounted
throttle lever and spark con-
trol lever

Clutch pedal for operating
clutch

Engine flywheel containing
dutch

Service brake pedal

Accelerator pedal, often called
foot-throttle

Service brake rods leading to
actuating mechanism of ex-
ternal contracting band
brakes on brake drums
bolted to rear wheels

Rear wheels

Rear springs, of the scroll full-
elliptic type

Spring shackle

Emergency-brake lever

Emergency-brake-lever rods
leading to actuating mechan-
ism of internal expanding
emergency brakes on inside
of brake drums

Emergency-brake equalizer bar

Quadrant, or bracket, for emer-
gency-brake lever and gear
shift lever

Gear shift lever

Gear shifting rods

Universal-joint assembly trans-
mitting power from dutch to
driving shaft

Driving, or propeller, shaft

Torsion tube housing the pro-
peller shaft

Transmission case forming part
of rear axle and containing
sliding-gear transmission

Right and left rear-axle housings

Digitized by

Google

U GASOLINE AUTOMOBILES § 1

61, Radius rods, or diagonal brace 66, Exhaust pipe, connecting

rods exhaust manifcdd with muf-

62, Service-brake shafts fler

6S, Emergency-brake shafts 66, Cross-member of frame, form-

64, Tumbuckles on brake rods, used ing forward support for tor-

for adjusting their lengths sion tube

SHAFT-DRIVE DBIVINQ-MECHANISH ARRANGEMENTS

10. In shaft-driven cars, there are in use at present several
diflFerent arrangements of the engine and clutch, the transmis-
sion, and the rear axle with reference to one another. Each of
the various arrangements has its own adherents among auto-
mobile manufacturers.

The preference of automobile purchasers has caused the
following general arrangment to be followed in practically every
shaft-driven pleasure car: The engine, with which the clutch,
in most cases, is combined, is placed at the front end of the car,
with its crank-shaft in the direction of the length of the car.
The transmission is then placed to the rear of the engine. In
the great majority of cars, use is made of an engine with either
four or six vertical cylinders. In both the Edwards-Knight
car and the Winton six-cylinder car, the clutch does not form
part of the engine, but is contained in the same casing as the
transmission. This, however, does not change the general
arrangement mentioned. In n^my cases the engine, the clutch,
and the transmission are combined into a single tmit; the com-
bination is then spoken of as a unit power plant.

An example of each one of the most common of the different
driving-mechanism arrangements is here given in the form of
a top view of the chassis of a car actually manufacttired. The
different cars presented do not constitute the only examples of
automobiles employing the particular arrangement of the
driving mechanism each one illustrates; those shown, however,
have been selected because they clearly exhibit the salient
features of each driving-mechanism arrangement.

!!• In Fig. 6 is presented a top view of the chassis of a Ford,
model T, automobile. In this car is employed a unit power

Digitized by

Google

Digitized by VjOOQ IC

16 GASOLINE AUTOMOBILES § 1

plant, the top of the cylinders showing at a. The clutch and
transmission are enclosed in the casing 6, and the drive to the
rear axle is by means of a shaft endosed in the housing c. The
engine is bolted rigidly to the frame d of the car. The rear
axle e is connected to the frame in this case by a single cross-
spring /; consequently, its distance from the frame is changing
continually with different loads in the car and under different
road conditions. Furthermore, the center line of the crank-
shaft and the center line of the driving shaft are not normally
in the same straight line, although they always intersect. From
this it can readily be seen that a jddding connection must be
made between the power plant and the driving shaft so as to
take care of any original disalinement, as well as that caused
by the compression and extension of the rear body spring.
This jddding connection is, in practice, made by a so-called
universal joint. In the case of the Ford car under discussion,
a single universal joint is employed at the forward end of the
propdler shaft, the joint being endosed in the casing g.

The application of the power of the engine to the driving
wheds tends to rotate the whole rear-axle housing around its
center line in a direction opposite to that in which the wheels
turn, and this tendency must be coimteracted by some means.
In the Ford car, the propdler shaft housing c is rigidly bolted
to the rear axle e and is connected by means of a ball joint to
the casing g; this housing c thus resists the torsional, or tiuning,
effect due to appljring the engine, and hence is often called the
torsion tube. This tube also resists the tendency of the axle
housing to rotate, when the brakes inside the brake drums h of
the rear wheds are applied, in a direction opposite that in which
rotation tends to take place when the car is driven by the engine.

In the Ford car, the rods i, called radius rods, hold the front
axle substantially at right angles to the frame d. The rods /,
which also are called radius rods, tie the torsion tube and rear
axle ends together, and hence serve as tie-rods. The rear axle
is confined lengthwise by hinging the torsion tube at its forward
end to the rear of the power plant.

The arrangement of the driving mechanism is, briefly, as
follows: A unit power pdant drives the rear wheds through a

Digitized by

Google

222B— 3

Digitized by

Google

18 GASOLINE AUTOMOBILES § 1

propeller shaft having a single universal joint at its forward
end, the shaft being endosed in a torsion tube.

12. A top view of the chassis of an Oakland, model **45,**
automobile is shown in Fig. 7. This car employs a tmit
power plant. The top of the eilgine cylinders is shown at a;
the clutch is next to the engine and is contained in the casing 6;
and the transmission is in the casing c. The propeller shaft d
is not housed, and a flexible connection between the rear
axle e and the transmission is made by means of two tmi-
versal joints /, one at each end of the propeller shaft. Rota-
tion of the rear axle housing in either direction tmder the
driving or braking stresses is prevented by a torsion rod, or
torsion bar, g. This rod is anchored at its rear end to the
rear-axle housing, and through a somewhat flexible connection
at its front end it is attached to a cross-member h of the frame i
of the car.

The frame is supported on fotu* springs. The front springs,
running lengthwise of the car, are placed underneath the frame
and hence cannot be seen in this top view; they are of the
semielliptic type, as is shown in S, Fig. 5. The two rear springs /
are also placed lengthwise of the car, but they are outside of
the frame and can therefore be clearly seen in the illustration.
These rear springs are of the three-quarter elliptic type, con-
sisting of one-half of the upper member and the whole lower
member of the full-elliptic spring shown at 38, Fig. 5. Support-
ing the frame of the car on four springs placed lengthwise is
by far the most common method of support. The front ends
of both the rear and front springs are hinged to the frame, and
as they are also bolted at their middle to the front and rear
axles, they serve to hold the two axles at right angles to the
frame and also confine them lengthwise; hence, no radius rods
are fitted or required.

The arrangement of the driving mechanism is, briefly, as
follows: A tmit power plant drives the rear wheels through
an tmhoused propeller shaft with universal joints at each end,
a torsion rod, or torsion bar, preventing the rotation of the rear-
axle housing.

Digitized by

Google

Digitized by

Google

20 GASOLINE AUTOMOBILES § 1

13« A top view of the chassis of a Rambler, "Cross-Country"
model, automobile is shown in Fig. 8. In this car, the engine
and the clutch form one tmit, the engine being shown at a and
the clutch at 6. The transmission c is motmted on the end of
the propeller-shaft housing d, which, in turn, is rigidly bolted to
the rear-axle housing e. This can be seen very clearly in Fig. 9,
which shows the rear axle e, together with the propeller-shaft
housing d and the transmission <;, removed from the chassis.
As the rear axle and the transmission are permanently alined,
the propeller shaft inside the housing d, which also serves as a
torsion tube, has no tmiversal joints. The transmission is
hinged to a cross-member /, Fig. 8, of the frame g. The power

Pig. 9

of the engine is transmitted through the clutch to the trans-
mission through a short driving shaft h having a tmiversal
joint at each end.

The front springs are hinged to the frame at their forward
end and bolted at the middle to the front axle; thus, they confine
the axle lengthwise and also hold it at right angles to the frame,
and hence no radius rods are needed. The front springs are
placed directly tmdemeath the frame. The rear springs i, Fig. 8,
are on the outside of the frame, and their lower half is bolted
at the middle to the rear-axle housing. The forward ends of
the lower half of the rear springs are attached to the frame, and
the rear ends to the upper half of the rear springs, by swinging
links, called shackles; consequently, the rear axle is not confined
lengthwise of the car by the rear springs and hence radius
rods /, are employed to hold the rear axle, at all times, at right
angles to the frame, as well as to confine it lengthwise.

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 21

Summed up briefly, the arrangment of the driving mechanism
is as follows: The engine and the clutch form a unit that

drives the transmission through a short shaft with double
universal joints, the transmission being carried by the forward
end of the torsion tube enclosing the propeller shaft.

Digitized by

Google

22 GASOLINE AUTOMOBILES § 1

14. A top view of the chassis of an Overland automobile
model 69, is presented in Fig. 10. In this car, the engine and
the clutch fonn a unit, the engine being shown at a and the
clutch at 6. The transmission c is motmted on the rear axle d,
and the propeller shaft is housed inside the torsion tube e,
which is bolted to the forward end of the transmission case
and is hinged to a cross-member / of the frame. The power of
the engine is transmitted from the clutch to the driving shaft
through a single imiversal joint g.

Some other manufacturers of automobiles using the same
arrangement of engine, transmission, and rear axle as the
Overland here shown employ two universal joints between the
clutch and the driving shaft.

The front springs are semielliptic, are placed directly imder
the frame, and are hinged to it at the front. Their rear ends
are shackled to the frame, and they are bolted, at their middle,
to the front axle, which is thus confined lengthwise of the car
by the springs. The rear springs are of the three-quarter
eUiptic type, like the rear springs of the Chalmers car shown
in Fig. 1. The lower half of each rear spring is shackled at the
front to the frame, and at the rear to the upper part of the
spring, and is bolted at the middle to a rotatable spring seat
on the rear-axle housing; consequently, the rear springs in
themselves do not hold the rear axle lengthwise of the frame.
This is done, however, by hinging the forked forward end of the
torsion tube to the cross-member /, as shown, and tying the
front end of the torsion tube to the rear axle ends by the tie-
rods h.

This arrangement of the driving mechanism, summed up
briefly, is as follows: The engine and the clutch form a xmit
that drives the propeller shaft housed in a torsion tube through
either a single universal joint or through two imiversal joints,
the transmission being carried by the rear-axle housing.

16. In Fig. 11 is illustrated a top view of the chassis of a
Packard, model 48, automobile. In this car, as in the Overland,
the engine and the clutch form a imit. The engine is shown at a,
and the clutch is enclosed in an extension b of the crank-case.

Digitized by

Google

Digitized by

Google

24 GASOLINE AUTOMOBILES § 1

The transmission is mounted in a casing c that is bolted
to the rear-axle housing, the power being transmitted from
the engine through a propeller shaft d that is not enclosed.
The propeller shaft is provided with two tmiversal joints e
and /, which allow for lack of alinement between the engine
shaft and the rear axle. A torsion rod g is attached at one end
to the transmission casing, and at the other end to a cross-
member h of the frame, to which it is connected by means of a
spring connection that allows for vibration due to play of the
body springs.

The front springs i are of the semielliptic type, being shackled
to the frame at the rear by means of a link and bolts and hinged
to it in front. The rear springs / are of the three-qtiarter
elliptic type, like those on the Overland and Chalmers car,
the lower half being shackled to the frame and to the upper part,
and the upper quarter being attached by spring clips to the
frame. The rear springs are fastened to the axle by spring
clips k. The rear axle is held in alinement with the frame
by two radius rods located directly below the side members of
the frame. On accoimt of their position they cannot be seen
in Fig. 11.

The foregoing arrangement summed up briefly is as follows:
The transmission is mounted on the rear axle and is driven
from the engine through an exposed propeller shaft with two
xmiversal joints, the tendency of the rear axle to turn being
overcome by a separate torsion rod.

16« Another form of shaft-drive mechanism, different from
any thus far described, is illustrated in Fig. 12, which shows
the top view of a 35-horsepower chassis of the Fiat automobile.
In this car, the engine, with its clutch, and the transmission,
are enclosed in separate casings. The tops of the four engine
cylinders, which are cast in one piece, are shown at a; the
clutch is enclosed in the casing 6, which is bolted to the flywheel,
and the transmission is carried in the housing c. Power is
transmitted to the rear axle through a propeller shaft that
turns inside of the tube d, the tube being an integral part of the
pressed-steel axle housing. A coupling is provided in the short

Digitized by

Google

Digitized by

Google

26 GASOLINE AUTOMOBILES § 1

shaft e, which connects the clutch and the transmission, and a
universal joint / is located at the forward end of the propeller
shaft to allow for any disalinement. The torsion tube d, which
prevents rotation of the rear axle housing, is supported at the
front by a yoke g which is hinged to the frame of the car.

The front springs h are of the usual semielliptic type, and the
rear springs i, of the three-quarter elliptic type. The front
springs are^ hinged at the front and shackled at the rear, while
the rear springs are shackled both at the front and the rear and
are attached to the rear axle by means of the spring clips /. All
four of the springs are placed lengthwise with the frame. Besides
performing its usual function, the propeller shaft housing d
keeps the rear axle in alinement with the remainder of the car.

In brief, the arrangement shown in Fig. 12 is as follows:
Power is carried from the engine and clutch through a short
shaft and coupling to the transmission, which is supported by
the frame; thence, through a single universal joint and an
enclosed propeller shaft to the rear axle.

17. Still another form of arrangement of the driving
mechanism in a shaft-driven car is illustrated in Fig. 13, which
shows the chassis of the Reo the Fifth automobile. In this
car, the propeller shaft is provided with two universal joints
and is not housed, separate torsion rods being used to prevent
the rear-axle housing from tiuning.

The tops of the engine cylinders, which are cast in pairs, are
shown at a. The clutch is enclosed in the case 6, and the
transmission, in the housing c, power being transmitted to the
rear axle through the propeller shaft d and the imiversal joints e
and /. The clutch is coimected to the transmission by the
shaft g, which is provided with the flexible coupling h to allow
for lack of alinement. The rear-axle housing is prevented from
rotating by two torsion rods i (one of which is directly tmder
the other) that are rigidly attached to the differential casing
at the rear, and fastened by a flexible connection to the cross-
member y at the forward end.

The front springs, which are hidden from view by the frame,
are of the semieUiptic type and are attached in the usual manner.

Digitized by

Google

Digitized by VjOOQ IC

28 GASOLINE AUTOMOBILES § 1

The rear springs k are of the three-quarter elliptic type; the
bottom half of each one is hinged to the frame at the forward
end by means of a bracket and bolt, and is shackled to the
upper part of the spring at the rear. These springs are rigidly
bolted to the rear-a^e spring seats and serve to hold the axle
in alinement with the remainder of the car.

Summed up briefly, the arrangement is as follows: The
power developed by the engine is transmitted through a clutch
and a short shaft and flexible coupling to the transmission;
thence, by means of an unhoused propeller shaft having two
universal joints, to the rear axle, a separate torsion member
being employed to prevent the axle housing from turning.

CHAIN-DBIVE DBIVINO- MECHANISM ARBANOEMENTS

18. Practically all chain-driven pleasure cars now being
built are of the double chain-driven type. This type of car is
provided with a countershaft that is driven from the engine
through a propeller shaft and that, in turn, drives the rear
wheels through two chains.

.19. A top view of the chassis of a six-cylinder, type 19,
Chadwick automobile is presented in Fig. 14, which shows the
arrangement of the various parts. In this car, the transmission
and the engine with its clutch are separate imits. The tops of the
engine cylinders are shown at a, the clutch being incorporated
in the flywheel 6; the transmission is enclosed in the casing c,
which is located at the coimtershaft d. Power is carried from
the clutch to the transmission by an tmhoused propeller shaft
that is located directly under the longitudinal brace e and is
provided with a imiversal joint at its rear end. It is to be
noted that the coimtershaft is driven exactly like the rear axle
in some forms of shaft-driven cars, except that only one imiversal
joint is required because the coimtershaft is carried by the
frame, and hence the alinement is not disturbed by spring
deflection. From the countershaft, the rear wheels are driven
by chains enclosed in the cases / and g. These chains run on
sprockets attached to the ends of the countershaft and to the

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 29

wheel hubs. The
wheels turn on a sta-
tionary, or dead, axle h.
The countershaft
housing , or differential
housing, i is prevented
from turning by the
braces /, and the rear
axle and countershaft
are held in alinement
with each other by
means of radius rods,
which form a portion
of the chain cases.

The front springs,
which are beneath the
frame and therefore
not visible in the illus-
t tration, are of the
^ semielliptic type and
are shackled at the
rear and hinged in
front. The rear spring
is of the platform type.
It is composed of the
two-side members fe,
which are ordinary
semielliptic springs,
and the rear member /,
which is an inverted
semielliptic spring
shackled to the rear
ends of the side
springs. The forward
ends of the side mem-
bers k are shackled to
the frame, and the rear
member I is attached

Digitized by

Google

30 GASOLINE AUTOMOBILES § 1

to it by means of a bracket at its center. Thesprings are rigidly
attached to the rear axle, which is held in alinement by the two
raditts rods.

Briefly, the arrangement of the driving mechanism of this
chain-driven car is as follows: The power of the engine is
transmitted through a clutch, a propeller shaft, a universal
joint, and a transmission to a countershaft, from which the
rear wheels are driven by means of chains and sprockets, the
propeller shaft being imhoused, with braces holding the coimter-
shaft casing in position.

BODIES AND ACCESSORIES

TYPES OP BODIES

GENERAL CLASSIFICATION

20. The body is that part of an automobile which pro-
vides accommodations for the carriage of passengers. It is
the superstructure that rests on the frame of the chassis, to
which it is fastened in such a way that it may readily be removed
to facilitate repairs or to make possible the substitution of
one style of body for another.

21. Bodies may be classified under two heads, namely,
open bodies and closed bodies. The former are used for run-
ning around town and for touring in summer, while the latter
are popular for winter use. The folding tops with which the
open bodies are usually equipped afford protection from sun
and rain to both the driver and the passengers. Closed bodies
are often fitted with side curtains, by means of which the space
between the driver's seat and the wind shield at the dash is
entirely closed, thtis protecting the driver in extremely cold
winter weather. The side curtains are provided with large
celluloid windows through which can be seen clearly the mirror
that gives the operator a good view of the road at the rear of
his car. Closed bodies have recently been brought out in

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 31

which the driver is protected in the same maimer as the pas-
sengers; that is, the driver's seat is fully enclosed by the dash
and wind shield in front and by permanent side doors with
glass windows at the sides. Closed bodies are frequently
provided with means for heating them, and they are often
supplied with luxurious accessories, such as speaking tubes,
flower holders, mirrors, and electric lights.

OPEN BODIES

22. Types of Open Bodies. — ^Automobiles having open
bodies consist of two general types — runabouts and touring cars.
The term runabout is applied in a general way to all Ught cars
having a single seat for two or three passengers, or a seat in
front for two passengers and a seat behind, called a rumble
seat, for one passenger. The touring-car body differs from
the runabout body in that it has a tonneau, or rear-seat, sec-
tion made wide enough to seat comfortably either two or three
persons. The tonneau is sometimes also provided with two
side seats that can be folded up out of the way when not in use,
so that the seating capacity of a touring car may be four, five,
six, or seven persons.

23. Rrmabouts. — ^In Fig. 15 (a), (6), and (c) are shown
three automobiles belonging to the runabout class. View (a)
shows an ordinary two-passenger runabout without doors,
the space on the sides between the dash and the seat being left
open. A tool chest nriay be carried on the rear, and in some
cars the gasoline tank is also carried in this position. Some-
times a supplementary, or rumble, seat is placed on top of the
tool chest, thus adapting the car for three persons.

24. The open-door runabout just described has gradually
given way to the more popular foredoor, or torpedo, runabout,
an example of which is presented in view (6). A characteristic
featiu-e of the torpedo body is the closing of the space on the
sides between the seat and the dash by doors called foredoors.
Sometimes a foredoor is placed on only one side of the car
and a blind door, or one that cannot be opened, on the other

Digitized by

Google

GASOLINE AUTOMOBILES

§1

side. The dash on this type of car is usually extended toward
the driver's seat in the form of a cowl^ as is shown in the illustra-
tion, thus affording protection to the dash equipment. How-
ever, some torpedo bodies are made with a straight dash.
Some makers style this form of runabout a roadster, and occa-
sionally the seat is made wide enough to accommodate three,
when it becomes a sociability torpedo roadster. The term road-
ster is sometimes applied to a four-passenger car of the touring-
car type.

25. The raceabout, or semiracer, as shown in Fig. 15 (c),
is a two-passenger runabout having the seats placed very low

and the steering colimm inclined, or raked, at an extreme angle.
This type of car is usually provided with a high-power engine
and is not much used for ordinary purposes. The racer differs
from the semiracer in that it is stripped of fenders, running
boards, and all body work except that actually required to
support the two individtial seats with which such cars are fitted.
This car is, of course, used only for racing purposes, and is pro-
vided with a high-power engine and an tmusually large gasoline
tank.

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 33

26. Touring Cars. — ^The common type of touring car,
such as is illustrated in Fig. 15 (d), is almost invariably fitted
with foredoors, as well as doors closing up the space on the
sides between the front and the rear seats. Ordinarily, the
front seat accommodates the driver and one passenger and the
rear seat is made wide enough for three passengers. A seven-
passenger car is made by adding to this seating arrangement
two folding side seats that are carried in the tonneau. In
some cases, the control levers are located in the center of the
car, so that both foredoors are used, and in other cases the con-
trol levers are on the side and the door on that side is a blind
door. In still other cars, the control levers are located on the
side and both foredoors are used, although it is rather incon-
venient to use the door on the same side as the levers. The
dash is often made with a cowl in order to protect the equip-
ment located on it. The touring car is usually provided with
a top that can be folded back out of the way when not in use.

27. In Fig. 15 {e) is shown the so-called haby tonneau, or
toy tonneau, type of touring car. This form of body differs
from the common type of touring-car body in that the rear
seat provides room for only two passengers, and the tonneau is
shorter, so that there is less room between the rear seat and the
back of the front seat than in the regular touring car. The
car shown in the illustration is not provided with foredoors,
but it has doors that close the space on the sides between the
seats; foredoors, however, may also be fitted.

28. The term phaeton is very often appUed to cars of the
touring-car class that carry four passengers and are similar in
appearance to the toy-tonneau type. As previously men-
tioned, some makers designate one style of four-passenger
touring car as a roadster.

What is commonly known as a close-coupled touring car is
one having a body of the toy, or two-passenger, tonneau variety,
the rear seat being located so that the passengers are either
in front of the center line of the rear axle or just over it. In
touring cars of the regular type, the rear-seat passengers are
back of the center line of the rear axle.

222B— 1

Digitized by

Google

GASOLINE AUTOMOBILES

§1

CXiOSED BODIES

29. Types of Closed Bodies. — Closed bodies for auto-
mobiles are made in a variety of forms, from those used on the
taxicab, which is built for service only, to the palatial body of
the high-priced limousine, upon which no expense is spared
to secure the greatest possible amount of beauty and luxury.
The popular forms of closed bodies are the coup4, the litnousine,
the Berline body, the landaulet, and the taxicab.

30. CJoui)^. — ^The coup^, an example of which is shown in
Fig. 16 (a), is a type of closed body usually designed for carry-

PlG. 16

ing two or three persons facing forwards. A folding seat is
sometimes provided, in which case the additional passenger
sits with his back toward the front of the car. This car is

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 35

especially adapted for the tise of physicians in cold and stormy
weather, for women out shopping, and so on.

31. LLmousiiie. — For private use, the limousine body
is the most poptilar of bodies of the closed type. It affords
a maximum of comfort, combined with an elegant luxurious-
ness not common to other types of closed bodies. As shown
in Fig. 16 (6), the upper part of the doors and body is made
up of glass set in a sash to form windows that may be lowered
into recesses provided to receive them. Thus, when the weather
is warm the passengers need not suffer from heat or lack of
fresh air. The glass partition back of the driver's seat is some-
times arranged so as to swing upwards against the roof, from
which it is suspended. The driver's seat is sometimes enclosed
by foredoors, as in view ((;), such a body being styled a foredoor
limousine.

32. Berline Body. — ^The Berline type of body is shown
in Fig. 16 (c). This body differs from the limousine bgdy in
that the front seats are entirely enclosed in the same manner
as the rear seats. It is also a very elegant body and is tised
only on high-priced cars.

33. Landaulet. — -For use in the suburbs or in the city,
a type of closed body known as the landaulet is very popular.
As shown in Fig. 16 (d), an extension of the top covers the
driver's seat, and a wind shield in front affords further protec-
tion to the driver in cold and rainy weather. In warm, pleas-
ant weather, the glass panels back of the driver, at the sides,
and in the doors may be let down into spaces provided to receive
them, and the rear portion of the body, being made of flexible
leather, may be folded down and back, transforming the pre-
viously closed body into one having some of the character-
istics of those of the open type. When, as is sometimes the
case, provision is made for removing the top over the driver's
seat, the framework back of it, and the upper part of the frames
of the side doors, the body is converted into one more nearly
like those of the fully open, or touring type.

Landaulets are usually provided with folding seats for two
passengers, who must ride backwards, the fixed rear seat

Digitized by

Google

36 GASOLINE AUTOMOBILES § 1

accommodating two or three passengers facing forwards. In
the horse-drawn vehicle from which the landaulet automobile
body takes its name, there are two seats facing each other
and the top is made in two sections so as to permit of folding
them back and thtis make an open carriage.

34. Taxicab. — ^The term taxicab is applied to automo-
biles of the closed-body type that are designed for hire to the
general public. To adapt it for use in summer as well as in
winter, in fair as well as in stormy weather, the taxicab body,
as shown in Fig. 16 {e), is made with a top that may be folded
down and back, as in the landaulet. The glass windows in
the side doors may be lowered into recesses provided for them,
as may also the windows at the back of the driver's seat. The
taxicab body is usually provided with one regular seat, which
comfortably accommodates two persons, and two folding single
seats, so that the car will carry foiu* passengers. The driver's
seat, which is only partly protected, is sometimes a single seat,
thus providing a place alongside the driver in which baggage
can be carried. Very often this type of car has the control
levers located in the center.

36. Miscellaneous Body Types. — Other types of auto-
mobiles employing closed bodies are known variously as the
brougham, the demilimousine, and the touring coach. The
brougliam and the demlllmouslne greatly resemble the
limousine, differing from it principally in having a smaller
seating capacity. The touring coacli is a car fitted with a
closed body designed to accommodate several persons besides
the driver. Large baggage-carrying capacity is provided at
the rear and on top of the coach, within which are provided
toilet accessories and every convenience for touring. These
bodies are commonly made to order and are fitted to standard
and special chassis.

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 37

ACCESSORY FITTINGS

AUTOMOBILB TOPS

36. Practically all automobile tops now in use belong to
one of two types; they are either cape tops or canopy tops.

37. Automobiles having open bodies, that is, runabouts
and totiring cars, are provided with flexible cape tops that

Pig. 17

can be folded back out of the way when not in use. Fig. 17
illustrates a cape top in place on a seven-passenger touring car.
This top may be folded back and protected by means of a slip
cover, when it will appear like the top seen in Fig. 15 (d) or {e).

Pig. 18

A cape top applied to a two-passenger runabout is shown in
Fig. 18. When folded back, this style of top has the appear-
ance of that shown in Fig. 15 (a) or (6).

Digitized by

Google

38 GASOLINE AUTOMOBILES § 1

Cape tops are provided with side curtaiiis, which are intended
for tise in winter or in stonny weather. When not in tise, these
curtains are ordinarily folded and carried under the rear-seat
cushion or in pockets especially provided for them.

38. Canopy tops are the rigid, non-folding tops used on
closed and semidosed bodies, as shown in Fig. 16. They were
originally used on open bodies, but because they were not
readily" detachable and had to be entirely removed when they
were not needed, their use was discontinued on this type of
body.

WIND SHIELDS

39. A wind sMeld is a device attached to the dash or
the cowl of an automobile body for the purpose of protecting
the occupants of the car from dust, rain, cold winds, etc. Wind
shields consist of glass supported by metal frames, and they are
usually so constructed that they may be folded or tilted at
different angles. In some cases, the glass is in one piece, form-
ing a solid mind shield, and in other cases it is in sections, which
are either hinged together, forming an ordinary folding wind
shield or a zigzag wind shield, or hinged separately, so that the
top section can be tilted independently of the other, forming
a rain vision wind shield. Practically all manufacturers include
a wind shield of one of these types in the regular equipment
on their cars.

In some of the older cars fitted with a cape top the place of
the windshield was taken by a storm front, which consists of a
waterproofed fabric fitted with a large celluloid window and
extending vertically from the dash to the top. This storm
front could be rolled up in fair weather.

40. A solid wind shield mounted on the cowl of the dash
of a touring car is shown in Fig. 19 (a). This type of wind
shield is made of a single piece of glass a contained in a metal
frame fe, and is hinged at c and d so that it can be inclined to
any angle. When not in use, it can be inclined forwards over
the cowl and out of the way.

Digitized by

Google

§1

GASOLINE AUTOMOBILES

41.' An ordinary folding wind sMeld attached to the
dash of a touring car is shown in Fig. 19 (fe). This syle of

Pig. 19

wind shield is composed of two sections a and 6 that are hinged
at c and d. The hinges are made so that the top part a will
stay in any position in which it is placed; hence, it can be

Digitized by

Google

40 GASOLINE AUTOMOBILES § 1

swung down below the line of vision of the driver as shown,
or placed in a vertical position above the section 6, giving the
maximnm height. This style of wind shield is perhaps more
used than any other type.

42. The zigzag .wind sliield, which is so named because
the lower part is always inclined at an angle, is shown in
Fig. 19 (c). Except for the position of its lower section, this
style of wind shield is the same as the ordinary folding type.
However, it is not employed so extensively as the folding
wind shield, its use being confined to the smaller cars, as, for
instance, runabouts and roadsters.

43. The raln-vlsion wind slileld, as illustrated in
Fig. 19 (d), is also made up of two sections; it differs from the
two preceding types in that the upper section is hinged near its
middle or at its top so that it can be tilted, as shown. When in
this position, a good view of the road can be obtained between
the sections; this is an advantage in stormy weather when the
glass may become wet and blurred. The upper section may also
be swtmg down, as in the folding type, by means of the arms
that support it, these being hinged at the top of the lower
section.

In some instances the lower section of a rain-vision wind
shield is so arranged that it may be inclined so as to deflect a
current of air into the front compartment; in that case it is
spoken of as a ventilating rain-vision wind shield.

44. In a strict sense, a speedometer is an instrument that
indicates the speed, either in miles or in kilometers per hour, at
which an automobile is traveling at any given time. It has
become customary, however, to combine with the speedometer
one or two odometers, which are instruments that measure either
in miles or in kilometers, the distance traveled by an automobile.
When only one odometer is used, it registers consecutively the
nimiber of miles or kilometers traversed by the car; no means
are provided for setting the instrument back to zero, and it is

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 41

spoken of as a season odometer. When a second odometer is
provided, it is always fitted with a device by which it can quickly
be set back to zero at the beginning of each trip; hence, it is
called a trip odometer. The setting-back device is always
arranged so that its use will not affect the reading of the season
odometer. At least one manufactiu'er incorporates in his
speedometer a grade meter, which registers, in per cent., the
grade that the car is ascending or descending. Thtis, as the
term is used at present, a speedometer is expected to have at
least one odometer incorporated in it, and it may have two
odometers and also a grade meter.

45. The speedometer is usually driven from one of the front
wheels; the reason for this is that these wheels have practically
no slip on the road in comparison with the rear wheels, or in
other^ words, their speed is always in proportion to the car
speed. The speedometer is usually mounted on the dash or the
cowl board, where it can readily be seen by the driver.

In applying a speedometer to a car, care must be taken to
obtain gearing that is suitable for the size of the front tire;
thus, a 36-inch front tire requires different gearing for the
speedometer than a 30-inch tire. Hence, the size of the front
tire should always be specified in an order for a speedometer,
so that the dealer will be enabled to forward the proper gears.
When improperly geared, the speedometer will indicate a
wrong speed as well as a wrong distance.

46. In the speedometers most widely used, the speed indi-
cation is obtained (1) by centrifugal force, (2) by magnetic
induction, (3) by pressure exerted by a fluid, or (4) by an
electric current.

In centrifugal speedometers, either the principle of the ordinary
fly-baU governor commonly used on steam engines is employed,
or the so-called ring governor is used. In either case, centrif-
ugal force acts on weights whose center of gravity is outside
the axis around which they revolve, the weights being revolved
by a flexible shaft driven from one of the front wheels. Centrif-
ugal force tends to make these weights fly away from the axis
of rotation.

Digitized by

Google

'42 GASOLINE AUTOMOBILES § 1

In magnetic speedometers, either a permanent magnet or a
series of pennanent magnets is revolved by a flexible shaft
from one of the front wheels, the revolving magnet or magnets
exercising a pull on a drum that can. oscillate against the resist-
ance of a coiled spring.

In fluid-pressure speedometers, either a liquid or a gas is acted
on by a suitable device that creates a pressure proportional

to the speed of the wheels, which
pressure is indicated on a dial
graduated to miles or kilometers
per hour.

In electric speedometers, a very
small dynamo is driven by one of
the front wheels, the voltage of the
current delivered by the dynamo
being measured by a voltmeter car-
ried on the dash of the car, this
voltmeter being graduated to miles
per hour instead of to volts. The
voltage of the dynamo used is
directly proportional to the speed
("^ at which its armature is revolved,

and hence is also proportional to
the speed at which the front wheels
revolve.

47. The Standard speedome-
ter, which is shown in section in
Fig. 20 (a) and in perspective in (6),
belongs to the class of speedometers
operated by centrifugal force. It
<"*> has two weights a that are free to

^'°" ^ slide on the rods 6, which are hinged

to the stem c. This stem has motmted on it two segments d
whose teeth engage those of a rack e that is movable in a
longitudinal direction. An arm / is clamped to the spindle of
each segment, and the free end of each arm has hooked to it
a coiled spring g. Each of the sliding weights a carries four

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 43

pins fe, two on each side of each segment d, between which fits
loosely a cross-pin i carried by each segment. The flexible
shaft driven by one of the front wheels rotates the stem c, and,
tmder the influence of centrifugal force, the weights a slide out-
wards; in doing so, the weights rotate the segments d, thereby
putting tension on the springs g, until the centrifugal force of
the weights equals the spring tension. The rotation of the
segments moves the rack up or down; the movement of the
rack is, by means of the pinion ; and the bevel gears k and /,
transmitted to the pointer m moving over a scale graduated
in miles per hour.

The odometer part of the speedometer is purposely omitted
in the sectional view in order to show the speed-indicating
mechanism more clearly.
A knob n, view (6), is used
for resetting the trip odome-
ter to zero.

48. The speed-indicat-
ing mechanism of the Jones
speedometer is shown in
Fig. 21, all the odometer
parts being removed for the
sake of clearness and the
case being partly broken

. . Fig. 21

away. A rmg governor

having the shape shown at a is employed. This governor
is pivoted by the pin b to the steel shaft c, which is rotated by
a flexible shaft d driven by one of the front wheels. The rota-
tion of the shaft c causes centrifugal force in the ring a, making
it tend to assimie a position at right angles to the shaft; this
tendency is resisted by a coiled spring e that is compressed
by the motion of the ring until the centrifugal force of the
ring and the spring tension are equal. At very high speeds,
an auxiliary spring/ comes into action. A brass tube, to which
is attached the brass spool g, can slide along the shaft c, and it
is connected to 'the ring a by means of a link h; consequently,
as the ring moves toward a position at right angles to the

Digitized by

Google

44 GASOLINE AUTOMOBILES § 1

shaft, the spool g is moved to the left. In doing so, the spool
pulls around a cam i that is pivoted by the shaft /, a pin k
rigidly attached to the cam i engaging the slot of the spool.

The face of the cam
bears against a pin /
carried by the link m,
which is hinged to an
ann fixed to a shaft
carrying the pointer n
that, in the assembled
instrument, moves
over the graduated
scale, showing the
speed. The cam
pushes the link m to
the left, thereby rota-
ting the pointer n. A
coiled spring o insures
that the pin / is always
in contact with the face
of the cam t, its one
end being attached to
the shaft that carries
the pointer.

49. The Stewart
multipolar speedome-
ter, a perspective view
of one model of which,
with enough of the
casing and dial broken
away to show the

speed-indicatingmech-

(^) anism, is presented in

^'^•^ Fig. 22 (a), belongs to

the class of speedometers operating by magnetic induction.

The rotor a is made of a non-ferrous metal and has inserted

in it four permanent magnets 6. This rotor is mounted on

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 45

a pair of ball bearings and is revolved by the bevel pinion c
on the solid driving shaft d that meshes with the internal gear e.
The shaft d, in turn, is driven from one of the front wheels by a
flexible shaft, not shown. The central stud around which the
rotor revolves is recessed and has at the bottom of the recess
a jeweled bearing for one end of the shaft /, the second bearing
for this shaft being in the stationary plate g. A circular disk fe,
made of an alloy having a low electrical resistance, is fastened
to the shaft /; a pointer i is also attached to the same shaft.
One end of a hair ^ring / is fastened to the shaft /, its other
end being attached to the stationary plate g. It will be observed
that there is no mechanical connection between the rotor and
the rotatable disk h.

In operation, the revolution of the rotor causes the disk h to
revolve in the same direction, this tendency being resisted by
the hair spring ;, and, consequently, the disk h turns imtil
its tendency to revolve just balances the tension of the hair
spring. The tendency of the disk ft, and hence of the pointer t,
to revolve is proportional to the speed of the rotor; thus, for
each change in the car speed, the disk h assimies a new position,
thereby indicating the speed on the dial by means of the pointer
moving with the disk.

50. Experience has demonstrated that, under great changes
of temperature, the electric resistance of the disk pulled around
by the magnets of magnetic speedometers is subject to change;
under such conditions, therefore, a magnetic speedometer is
liable to indicate wrong speed. To overcome this faxilt, many
Stewart speedometers are fitted with a temperature-compen-
sating device, which is shown in Fig. 22 (6), applied to the hair
spring of a different model of instrument from that shown in (a) .

The compensator consists chiefly of a laminated strip a of
steel and brass that is coiled as shown, one end of it being
anchored at 6, and the other end being free. The free end of
the strip uncoils slightly when the temperattire rises, because
the brass in it expands more than the steel; and it coils up
more when the temperature drops, because the brass contracts
more than the steel. The movement of the free end of the

Digitized by

Google

46 GASOLINE AUTOMOBILES § 1

strip a is transmitted to a sector c that meshes with a pinion, to
which the one end of the hair spring d is attached. The
uncoiling of the strip lengthens the hair spring on a hot day,
and the coiling up of the spring shortens the hair spring on a
cold day, thtis causing it to offer more resistance to the pull of

the magnets of the
rotor. Changes in the
electrical resistance of
the disk pulled around
by the rotor magnets
are thus compensated
1 for by increasing or

decreasing the resist-

ance of the spring op-

_.^^ posing the pull of the

rotor magnets.

/ 51. Practically all

speedometers are
driven in the manner
indicated in Fig. 23 (a) .
^^ A large spur gear a is

bolted to the hub of
one front wheel and
central with the hub;
with it meshes a
pinion b fastened to a
shaft inside the tube c.
This shaft, through a
(b) series of four bevel

^'°-^ gears enclosed in the

casing d drives another shaft in the tube e, to which the flexible
shaft leading to the speedometer is attached. The casing d is
made in two halves that can swivel on each other; conse-
quently, as the lower part is held rigid with reference to the
wheel, the upper part can swing in a horizontal plane. By this
means the flexible shaft is not subjected to bending every time
the front wheels are turned, and its Uf e is thus greatly increased.

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 47

The comhiiiation of the casing parts with its four bevel gears
and its two soUd shafts forms what is variously known as a
flexible-joint drive, a swiveUjoitU driven or a pivoi-joint drive.

The internal construction of a swivel joint, as used in connec-
tion with the Hoffecker speedometer, is shown in (6). The
bolt a fonns the pivot on which the two parts of the casing
can swivel; it has motmted on it
loosely the double bevel gear 6,
which transmits the motion of
the lower shaft to the upper shaft.

52. The flexible shaft used &

with speedometers consists of two
members, namely, a protective
flexible casing and a flexible
driving member. The flexible
casing may be metallic tubing,
or it may be braided and water-
proofed fabric over a flexible
metallic core, inside of which is
the flexible driving member. In
Fig. 24 are shown short sections
of three different types of flexible
shafts in common use.

In view (a) is presented the
flexible shaft used with the
Hoffecker speedometers. The ca-
sing consists of a metallic core a

coiled from flat stock; this core <'^> ^> ^^^

is covered with two layers b and c ^°* ^

of waterproofed flexible braided fabric. The flexible driving
member d consists of seventeen strands of very fine piano wire
that are woven together.

In the flexible shaft used with the Warner speedometer, and
shown in view (6), the flexible casing consists of a flexible steel
core a made by coiling from two strips of flat stock; this core is
slipped inside a r^ular flexible brass tube fc, such as is used for
automobile horns. The brass tubing, in turn, is protected by

Digitized by

Google

48 GASOLINE AUTOMOBILES § 1

a casing c having the form of an ordinary helical spring. The
flexible driving members consist of a series of cylindrical links d
to which are hinged flat links e, pins being passed through holes/
that are somewhat larger than the pins. Owing to the shape
of the slots in the links d, considerable motion in all directions
is possible between all links.

The Stewart speedometer uses the flexible shaft presented
in view (c). The casing consists of the usual core a coiled
from flat stock; this is kept in shape and protected by the
flexible brass tube fc. The driving member consists of a series
of like links c hooked together, the two hooks of each link
being at right angles to each other.

Digitized by

Google

GASOLINE AUTOMOBILES

(PART 2)

AUTOMOBILE RUNNING GEAR

WHEELS AND AXLES

WHEELS

!• Types of Motor- Vehicle Wheels. — Most automobiles
are eqtdpped with wooden wheels of the so-called artillery type,
a form of wheel used on gun carriages and one capable of with-
standing severe shocks imder heavy loads. Early types of
automobiles were equipped with wire wheels; that is, wheels
having wire spokes. Such wheels are again coming into use
on accotmt of the progress made in wire-wheel construction.
Wooden wheels of the artillery type are known as compression
wheels, because the spokes in the bottom half of the wheel carry
the weight and are therefore in compression. Wire wheels are
known as suspension wheels, because the spokes supporting the
hub are in tension, that is, drawn up tightly, and the load may
be said to be suspended by these spokes.

2. Wooden Wheels. — Artillery wheels are usually con-
structed with the spokes set in a single circle aroimd the hub,
between the flanges of which they are securely clamped by
means of bolts. As compared with wire wheels, this type of
wheel is more easily cleaned, is more elastic, and is not sub-
ject to deterioration on acdoimt of rusting. Ordinarily, the

COPVm«HTBO BY INTBRNATIONAL TKXTBOOK COMPANY. ALL RIOMTS RnSIIVBO

222B— 5

Digitized by

Google

50 GASOLINE AUTOMOBILES § 1

spokes lie in a plane perpendicular to the longitudinal center
line of the hub, but in a few cases they are dished; that is, they
are set inwards at the hub and are not perpendicular to the
center line of the hub. The dished construction is claimed by
some manufacturers to give the wheel greater strength to resist
lateral or sidewise stresses, as when turning comers. In most
automobiles equipped with wooden wheels, each front wheel

Pig. 1

has ten spokes and each rear wheel, twelve; although, in some
cases, both front and rear wheels are provided with twelve
spokes each.

3. The construction of a typical automobile wheel is shown
in Fig. 1, which illustrates the front and rear wheels used on
the Packard car. Part of each wheel is cut away in order to
show the arrangement of the pafts at the hub. Except for the
different ntunber of spokes and the different requirements at
the hubs, the construction of the two wheels is identical. As
shown, they are fitted with demountable rims a, which can be
taken off quickly by removing the nuts 6 and the cleats c. The
front wheel, which is illustrated in view (a), contains ten spokes d
set around the hub in a single circle and held in place by bolts e

Digitized by

Google

S 1 GASOLINE AUTOMOBILES 61

that pass through the hub flanges. The felloe f and the spokes
are bound in place by the steel rim g, which is pressed over the
felloe.

In view (6) is shown the rear wheel, which contains twelve
spokes h arranged in a single circle, like the spokes in the front
wheel. These spokes are held in place by bolts i that pass
through the hub flanges and bolts / that are used for attaching
the brake drum k. The bolts / pass through the brake drum Jfe,
the hub flange /, and the spokes, thus tying, or binding, these

Pig. 2

parts together. Part of the hole in the hub is squared in order
that the wheel may be driven by the squared end of the axle shaft.
The hub caps m and n are provided to keep dust and dirt
out of the hubs and to give the hubs a finished appearance.

4. Fig. 2 illustrates both the construction and the arrange-
ment of the spokes in the Schwarz patent wheel, which is used
on a large number of automobiles. The mitered joints at the
hub end of the spokes are made to overlap by using the mortise-
and-tenon joint. When the spokes are assembled, the tenon a
fits into the mortise 6, tenon c into mortise d, and the inner
tenons a and e are overlapped by the outer tenons / and g.
The spokes are thus so interlocked that they cannot work
loose, and they support one another in a compact, true

Digitized by

Google

52 GASOLINE AUTOMOBILES § 1

assemblage. The spokes are put together under pressure with
glue, and the appearance of the spokes at the hub when
assembled is as shown at the right in Fig. 2.

5. Wire Wheels. — ^For automobile use wire wheels are
constructed on practically the same principle as ordinary
bicycle wheels. Usually, the spokes are arranged about the
hub in two circles, one set of spokes being attached to the
inner hub flange and the other set to the outer hub flange.
All the spokes are tightened to exactly the same tension, so
that they hold the hub in a central position and equalize the
strain on the hub and the rim. The principal advantages

Fig. 3

claimed for wire wheels over wooden wheels are that they are
stronger and will withstand a greater driving stress in pro-
portion to their weight. It is also claimed that wire wheels
keep cooler than wooden wheels, on accotmt of their ability
to radiate heat more readily, and hence the tires are not affected
to so great an extent by the heat generated when rotating
rapidly.

6. An example of an American-made wire wheel is the
McCue wheel, one form of which is illustrated in Fig. 3 (a).
This wheel, as shown, contains two rows of spokes, one row being
attached to the inner part of the hub and the other row to the

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 53

outer part. There are forty-two spokes in the inner row and
twenty-eight in the outer row, so that the hub is suspended at
seventy points. Each spoke is fastened to the rim a by means
of a nipple 6, into which the spoke is screwed. The spokes are
in pairs; that is, two spokes are formed of one piece of wire,
which is passed through two holes in the hub casing and attached
at two different points on the rim. For example, the spokes c
and d are formed of the same piece of wire, which extends from
the rim through the hole e and is bent over on the inside of the
hub casing g and brought out through the hole /, from which
it extends to another point on the rim. The two spokes thus
formed cross at an
angle close to the hub,
as shown. In the
manufacture of the
wheel, all the spokes
are tightened to ex-
actly the same tension.

Fig. 3 (6) shows the
inner hub that fits in-
side the hub casing g.
As will be observed,
this inner hub is made
for a rear wheel and
carries the brake

drum h. The inner ^'""'^

hub and the outer casing are made with a taper fit, the part i
fitting into g and the long part ; fitting into k of the outer casing.
The driving strain is taken by pins / that engage with the
holes m in the outer casing. The wheel is held in place on
the inner hub by means of a nut n that screws on the end of
the hub and presses against the end of the outer casing, thus pre-
venting the parts from separating. The nut n is screwed in place
by means of a wrench o, which is provided with hooks p that
engage with projections on the nut. One of these projections
is shown at q and the other is covered by the safety latch r .

The end of the outer casing of the wheel hub is shown in
Fig. 4. The projection, or pin, that is covered by the safety

Digitized by

Google

64 GASOLINE AUTOMOBILES § 1

latch, shown in Fig. 3, fonns a pawl that extends through the
nut and engages with the ratchet teeth 5, Fig. 4. This pin,

or pawl, is fitted with a
coil spring that pushes it
out, disengaging it from
the ratchet when the
safety latch is moved to
one side. When the
wheel is to be taken off,
the wrench o. Fig. 3, is
placed on the nut and
Jiumed until the hooks p
engage the pins, or pro-
jections, on the nut.
This operation auto-
matically pushes the
safety latch r aside and
allows the pawl and
ratchet to become dis-
engaged. The nut can
then be unscrewed. In
putting on the wheel, the
nut n is first screwed on
the hub and then, when
the wrench is removed,
the safety ratchet snaps
back into place, forcing
the pawl into the teeth
on the ratchet s, Fig. 4,
and locking the nut and,
consequently, the wheel
in position.

It is to be noted that
the wire wheel just de-
scribed is a detachable
^°* ^ wire wheel; that is, it can

be readily removed. Generally, where these wheels are used, a
spare wheel is carried for use in case of tire trouble.

Digitized by

Google

S 1 GASOLINE AUTOMOBILES 55

7. Another form of McCue wheel is provided with three
rows of spokes, as is illustrated in Fig. 5, which is a sectional
view of a rear wheel, showing the inside construction of the
rear hub, as well as the arrangement of the spokes. The
axle shaft a, to which the wheel is fitted, turns freely in the
stationary tube b of the axle housing. The ball bearing c is
moimted on the outside of the tube 6; the inner wheel hub d,
which is keyed to the axle shaft, turns on this bearing. The
hub casing e fits over the inner hub d and is held in place by the
cap /, the driving stress being transmitted through the pins g.
The brake drums h and i are so bolted to the inner hub that
they rotate with it. The three rows of spokes are shown at /,
ife, and /, the rows ; and k containing the same number of spokes.
The spokes of this wheel are made separately, instead of in
pairs, as in the whefel illustrated in Figs. 3 and 4, each spoke
being attached to the wheel hub by having the end upset and
swaged, as shown at w.

The triple-spoke wire wheel is used where wire wheels are
fitted to an automobile that had previously been equipped
with wooden wheels, the third row being added to take up the
extra strain occasioned by setting the rim in for the purpose
of keeping the wheel tread the same. On accoimt of the con-
struction of the rear axle used with wooden wheels, the brake
drums must be kept the same distance apart when wire wheels
are substituted; hence, it is necessary to set the wheel rim in
farther toward the automobile body, in relation to the hub,
than when the axle is built specially for wire wheels. The
extra strain set up by thus constructing the wheel is taken
by the row of spokes k.

8. Spring Wheels. — ^To obviate the use of pneumatic
tires, the maintenance and first costs of which are high, and
at the same time to secure the easy riding qualities of the
pnetmiatic tire, many inventors have given a great deal of
thought to the problem of producing commercially feasible
elastic, or spring, wheels. Numberless designs have been
produced, but spring wheels have not become popular. .

Digitized by

Google

66 GASOLINE AUTOMOBILES § 1

FRONT AXLES

9. The front axle of an automobile is made up of four
parts; namely, a bar carrying the spring seats upon which
the springs supporting the front part of the automobile rest,
two steering knuckles carrying the spindles on which the wheels
turn, and a cross-rod extending from one steering knuckle
to the other and by means of which the knuckles are tied together

Pig. 6

so as to move in imison when the wheels are swiveled in steer-
ing. The location of these four parts is shown clearly in Fig. 6,
which is a front view of one model of the chassis of the Winton
automobile. The main bar of the axle is shown at a, and at b
and c are located the spring seats upon which the front springs e
and / are carried. The steering knuckles g and h are pivoted
at the ends of the axle bar and are connected by the cross-rod i,
which, in this automobile, is located in front of the front axle.

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 57

More frequently, the rod i is located back of the axle, but in
every instance it performs the same service; that is, it forms
a connecting link between the steering knuckles.

On the majority of automobiles, the front axle bar is made
of a forged-steel I beam, as shown in Fig. 6. In a few cases,
however, the axle is made of a steel tube, in still other instances
the bar is of channel cross-section, and on at least one of the
smaller cars a wooden axle has been used. Front axles may,
then, be classified broadly as solid front axles, of which there
are a ntmiber of types, and tubtUar front axles.

10. Solid Front Axles. — Several types of solid front
axles having an I-beam cross-section are illustrated in Fig. 7,
which shows a top and a side view of each. In (a) is shown
the front axle of the Studebaker "20" automobile. The axle
bar a of this axle is made of a sted I beam, which is dropped
at the center to make it more elastic. This bar carries the
spring seats 6, upon which the front springs rest, and the spring
clips d, which hold the springs in place. The steering knuckles e
are pivoted in the yoked ends of the axle by the pins c, and they
carry the spindles /'upon which the front wheels rotate. The
knuckles are connected by the cross-rod A, which is attached
to the arms g by means of yoked ends. The rod h and the
steering knuckles are rocked to and fro when steering the auto-
mobile, by a rod i that is connected at its free end to tfie steer-
ing gear. The steering knuckles used on this axle are known
as the EUiott type. In this type, the knuckles fit between jaws
formed at the ends of the axle bar.

Another front axle of I-beam cross-section, but one that
makes use of steering knuckles of the reversed Elliott type, is
the McCue axle shown in (6). The different parts of this axle
perform the same functions as the corresponding parts in the
axle shown in (a), the steering knuckles in this case being rotated
by an arm a that is connected to the steering gear by means of
a nxi, not shown. It will be noted that in this case the steer-
ing knuckles have jaws fitting over stub ends of the axle bar.

The Winton axle, shown in (c), also makes use of an I-beam
cross-bar, but it uses \h&Lemoine type of steering knuckle.

Digitized by

Google

Q; nfiiiiniiiiii'aiimHiiiiiiij QaOiE

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 59

In this case, the steering knuckles
are rotated by means of an arm a
that is connected to the steering
gear by a rod, as previously ex-
plained in connection with the
McCue axle. In the Lemoine steer-
ing knuckle, no jaws are used; the
knuckle has a stub b that fits into a
corresponding hole in a boss c at
each end of the axle bar. The
"32" Hupmobile car uses a reversed
Lemoine steering knuckle, which
means that the spindle upon which
the wheel turns is at the top of the
axle bar instead of below it.

11. In Fig. 8 is shpwn a part
sectional and part front view of a

^ pressed-steel front axle, made in
i the form of a channel, as used in
some S. G. V. automobiles. The
main part of the axle a is fitted
with two end-pieces b that carry the
steering knuckles c. The steering
knuckles, which are of the reversed
Elliott type, are tied together by
the rod d, so that they receive the
same movement when operated by
the ann e. The wheel hubs are
shown in place at / and g, and the
spring clips that hold the springs
on their seats, at h and i,

12. Tubular Front Axles.

■ An example of a tubular front axle
is the Franklin axle, two views of
which are shown in Fig. 9. The
main axle bar is a steel tube a,
which is brazed to the steering

Digitized by

Google

Digitized by VjOOQ IC

§ 1 GASOLINE AUTOMOBILES 61

knuckles b. The axle is dropped, or bent downwards, at the
center to increase its elasticity. The springs are carried beneath
the axle tube by spring dips c that are bolted to the supports d.
The steering knuckles are tied together by the rod e^ so that
they move in unison, and they are operated from the steering
gear by means of the arm /. One road wheel g is shown in
part section in place on the axle, and it serves to illustrate the

Pig. 10

relative positions of the wheel and the steering knuckles. When
springs are placed beneath the axle, they are said to be
underslung.

13. Steering Knuckles. — In four-wheeled horse-drawn
vehicles, the spindles upon which the wheels revolve form an
integral part of the front axle, and steering is accomplished
by turning the entire axle about its center. In automobiles,
however, this construction is imdesirable because of the dif-

Digitized by

Google

62 GASOLINE AUTOMOBILES § 1

ficulty that wotild be incurred in steering by hand at high
speeds, as weU as the lack of strength that would result. In
order that the front axle bar of an automobile may be attached
rigidly to the springs, and to obtain easy steering by turning
the wheels through only a small radius, steering knuckles are
provided. Steering knuckles are devices pivoted at the
ends of the front axle of an automobile for the purpose of
supporting the front wheels and allowing them to be turned
without moving the axle bar.

14. A common form of the Elliott steering knuckle is

shown in place on the axle in Fig. 10, which is a view of the
right-hand front wheel and steering connections on the Abbott-

PlG. 11

Detroit automobile, looking from the rear of the car toward
the front. The steering knuckle a is pivoted in the yoke b
of the axle bar, and it is operated from the hand steering wheel
through the arm c, the reach rod d, and the steering-gear crank-
• arm c clamped to the steering gear-shaft /. The spindle g
upon which the road wheel h revolves is an integral part of
the knuckle. This steering knuckle is connected to the knuckle
on the left side of the car by means of the distance rod i, which
is attached to the arm /. When the steering wheel is turned.

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 63

the reach rod d is moved forwards or backwards by the arm e,
so that the kaudde, and, consequently, the road wheel, is
turned to the right or the left by the arm c. The other front
wheel is turned at the same time and in the same direction
by means of the distance rod i. The steering knuckle on the
left side of the automobile is exactly the same as that shown
in Fig. 10, except that the arm c is omitted.

15. In Fig. 11 is shown the left-hand steering knuckle
used on the Chadwick car. In this automobile, the steering
gear is located on the right-hand side, so that no reach rod arm
is necessary on this knuckle. The steering knuckle a has a
separable ann b con-
nected to the distance

rod c by means of a
ball-and-socket joint
at d. The steering-
knuckle pivot pin e
passes through the yoke/
and is prevented from
coming out by a nut and
a cotter pin on the lower
end. This knuckle is
also of the EUiott type,
the yoke being an in-
t^;ral part of the axle
bar.

A cross-sectional view p^^, ^^

of the Chadwick steer-
ing knuckle is illustrated in Fig. 12, which is lettered the same
as Fig. 11, wherever possible, so that the preceding explanation
may be applied to both illustrations. In Fig. 12, the wheel
hub g is shown in place on the spindle and the distance rod is
omitted in order to show the other parts more clearly.

16. Fig. 13 shows a cross-sectional view of the steering
knuckle used on the Steams automobile. It, too, is of the
Elliott typOf and differs principally from the Chadwick knuckle
in that the pivot pin bearings, or bushings, h and i are mounted

Digitized by

Google

64 GASOLINE AUTOMOBILES § 1

in the yoke ends instead of in the knuckle head, as shown in
Fig. 12|, and a plain thrust bearing /, instead of a ball thrust
bearing is used to support the load. In the Steams steering

knuckle, the wheel hub
is mounted on roller
bearings k, while in the
Chadwick it is mounted
on ball bearings.

17. An example of
the reversed Elliott
steering knuckle is

that used on the Fierce-
Arrow automobile. A
perspective view of this
'^" ^^ knuckle is shown in

Fig. 14, and a cross-sectional view, in Fig. 15. On referring to
these illustrations, which are lettered alike, it will be seen that
the spindle a and the yoke b form a one-piece steel forging, and
that this forging carries the wheel hub c on the bearings d and e.

Pig. 14

The enlarged portion g of the axle bar/ is pivoted in the yoke by
the pin h. It is to be noted that the steering-knuckle bearings,
or bushings, i and / are mounted in the yoke and that the yoke

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 66

turns on the pin A, which remains stationary with respect to the
axle bar. This fonn of construction is the rule in the reversed
£lliott type of steering knuckle, although in the ElUott type,

Fig. 15

as jtist explained, the bearing may be in the knuckle, or head,
as shown in Fig. 12, or it may be in the yoke, as in Fig. 13.
Figs. 14 and 15 show the right-hand steering knuckle viewed
from the front of the automobile. The knuckle is operated
from the reach rod by
means of the remova-
ble armfe and is tied to
the left-hand knuckle
by means of the dis-
tance rod /, which is
joined to the arm m
by the ball-and-socket
joint n.

18« A Lemoine
steering knuckle, ^^ ^^

as used on the Win-
ton automobile, is shown partly in section in Fig. 16; an outside
view of this tjrpe of knuckle, on the front axle, is shown in
Fig. 7 (c). As will be seen on referring to Fig. 16, no yoke is
employed in this knuckle, but the spindle a and the pivot pin b

222B— 6

Digitized by

Google

66 GASOLINE AUTOMOBILES § 1

are integral, and the pin rotates in bearings c and d in the axle
head e.

19. Steering Connections. — Fig. 17 illustrates the com-
plete steering system of the Pierce-Arrow automobile. This
system is presented to show the way in which many steering
systems are arranged and how turning the steering wheel a
to the right or the left causes a corresponding movement of
the front wheels. When the wheel a is rotated, a worm at
the lower end of the steering coltmin b causes the segment of a
worm-wheel with which it meshes to turn on its axle, thereby
causing the arm c to move backwards or forwards, as the case

Fig. 17

may be. The motion of the reach rod d is transmitted to
the steering arm e of the right-hand steering knuckle /, and
from the latter, through the knuckle arm g and the distance
rod A, to the arm i of the left-hand steering knuckle ;. The
two steering knuckles are thus made to move in imison to the
right or the left in response to a corresponding movement of
the steering wheel. When the wheel is ttimed to the right,
the reach rod d moves forwards, causing the front wheels to be
swimg around so that the car travels toward the right. Rota-
ting the wheel in the opposite direction causes the reach rod d
to be drawn back, so as to turn the front wheels toward
the left.

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 67

It is to be noted that on this automobile the steering wheel a
is located on the right-hand side, so that the reach rod d and
the arm e are also on the right-hand side. However, many

Pig. 18

manuf acturers now place the steering colimm on the left-hand
side of the automobile, in which case the distance rod and the
steering arm are also placed on that side. Generally, the dis-
tance rod that connects the steering-knuckle arms is located

Digitized by

Google

68 GASOLINE AUTOMOBILES $ 1

behind the front axle, as is indicated in Fig. 17, the object being
to protect it from damage that might result from obstructions
in the road; nevertheless, it is sometimes placed in front of the
axle, as is shown in Fig. 6.

20. On some automobiles, the reach rod extends across
the chassis, in which case it connects the lower end of the steer-
ing colimin with the steering knuckle on the opposite side of
the automobile. An example of this kind of construction is
illustrated in Fig. 18, which shows a top view of the forward
part of the chassis of one model of the Overland car. A worm
and a worm-wheel are located in the casing h at the lower end
of the steering coltunn a, jtist as is explained in connection
with Fig. 17; but they are so arranged that when the steering
wheel b is turned to the tight or the left the reach-rod arm is
rotated backwards or forwards crosswise of the chassis instead
of lengthwise. A movement of this arm causes a correspond-
ing movement of the reach rod c, and this, in turn, causes the
desired rotation of the road wheels d through the steering-
knuckle arms e and / and the distance rod g.

When the steering wheel is located on the left-hand side of
the automobile and a reach rod running cross wise of the frame
is employed, the reach rod extends to the steering knuckle on
the right-hand side.

21. Mounting Front Wheels. — ^In order that an auto-
mobile may be steered easily by hand, it is desirable that the
front wheels turn as nearly as possible on an exact pivot; that
is, that the pivot pin be as nearly as possible in line with the
point where the wheel touches the ground. This object is
accomplished in some cases by having the steering knuckles
constructed so that, while the pivot pins are vertical, the wheels
are inclined slightly and are closer together at the bottom than
at the top. In other words, a line x x, Fig. 9, drawn through
the center of one of the pivot pins will be nearer the center
line ^^ :v of the wheel at the point where it touches the ground
than at the hub. By thus bringing the bottom of the wheel
as near as possible to the center line of the pivot pin, the ease
with which the wheels may be turned in steering is increased.

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 69

The same object may be accomplished by keeping the wheel
vertical and inclining the steering-knuckle pin, or by inclin-
ing both the wheel and the pivot pin. The method last named
is illtistrated in Fig. 12, which shows a steering knuckle so
designed that both the wheel and the pin are set at an angle.

22. Ease of steering is accomplished in some automobiles
by making the hub of the front wheel hollow and placing the
st.eering knuckle in its center. In this way, the center of the
steering-knudde pivot pin is brought into exact line with the
center plane of the wheel, and maximum ease of steering is
produced because the wheel is turned on an exact pivot. An

Fig. 19

example of this form of steering knuckle and front axle is pre-
sented in Pig. 19, which shows a front view of the six-cylinder
Mannon car. The axle yoke a extends into the hub 6, so that
the center line of the steering knuckle c coincides with the center
plane of the wheel.

23. Caster Steering. — By means of certain particular
settings of the steering-knudde pivot pins, it is possible to
make the front wheels of an automobile keep automatically
in line with the rear wheels while the car is in motion, thus
tending to ntiake it go straight ahead. The principle involved
is either identical with that used in casters placed imder

Digitized by

Google

GASOLINE AUTOMOBILES

•■-^■"^^-~-

.. r-l-

Co q If Lb3^

fumittire or a modification
of it; for this reason, front
axles constructed on the
same principle are known as
caster steering axles.
This effect is accomplished
in three ways, as is illus-
trated in Fig. 20.

In the first method, which
is shown in view (a), the
steering knuckle a is slanted
so that the line A 5, which
passes through the center of
the pivot pin, meets the
ground at a point 6, which
is a short distance ahead
of the point c where the tire
touches the ground. It is
assumed that the front of
the automobile points in
the direction of the arrow x.
Slanting the steering
knuckles in the manner first
explained gives the same
steering effectas slantingthe
front fork of a bicycle; that
is, the weight of the automo-
bile tends to keep the front
wheels in line with the rear
wheels and to make the car
go straight ahead. It is to
be noted that in this case the
spring seatrf is not set square
with the axle but is tilted
slightly to allow the spring e
to be mounted horizontally.

The second method of
obtaining the caster effect

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 71

is shown in view (6). This method is exactly like that illus-
trated in view (a), except that the spring seat d is set square
with the pivot pin, so that both the spring and the pivot pin
are tilted in order to slant the steering knuckle.

In the third method of obtaining the caster steering effect,
use is made of the identical principle of the ordinary caster
that is used on furniture. The application of this principle
to a steering knuckle, as carried out in the B. and L. caster
front axle, is shown in (c), which presents a top view and a rear
view. The pivot pin a is set in front of the center line A B
of the axle and inside of the wheel hub b, which is made hollow.
By this arrangement, the center line of the pivot pin lies in
the center of the wheel, but when extended it meets the ground
at a point some distance ahead of the point where the tire
touches the ground. The wheel, then, has the effect of trail-
ing behind the pivot pin, just as the ordinary caster trails
behind its pivot, or bearing, and tends to keep the automobile
moving in a straight line.

RBAB AXLES AND H0USINO8

24. T^pes of Rear Axles. — ^Rear axles are of two gen-
eral types, namely, live rear axles and dead rear axles, depend-
ing on their construction.

A live rear axle is one that rotates or has a rotating part.
It not only carries a part of the weight of the car and the occu-
pants, but also serves to drive the rear wheels and thus propel
the vehicle.

A dead, rear axle has no rotating parts; the wheels are
driven by chains from a countershaft and they turn on spin-
dles on the ends of the axle. A dead rear axle serves only to
carry its proportionate part of the weight of the car and its
load, and fakes no part in driving the wheds.

25. In the majority of American-made automobiles use
is made at present of the live rear axle; the dead axle is
employed in only a limited number. The live axle is made up
of three principal parts, namely, a two-piece driving axle shaft,
a differential, and a housing that encloses the axle shaft and

Digitized by

Google

72 GASOLINE AUTOMOBILES § 1

the differential. That part of the housing which surrounds
the axle shaft is sometimes called the axle tube, and to it are
pinned and brazed or otherwise fastened the spring seats,
or blocks, to which the rear springs are fastened by means of
spring clips. Each half of the axle shaft is attached at its
inner end to the differential, which is located in the middle of
the axle, and at its outer end to one of the road wheels, which
it drives. The axle shaft is driven through the differential,
which consists of a set of gears so arranged that while both
parts of the shaft receive power, one part may turn at a higher
rate of speed than the other and thus allow the automobile
to go around a comer without causing one of the wheels to
slide. Usually, the differential is driven from the engine by
means of a shaft and bevel gears, or by means of a shaft driving
a worm that meshes with a worm-wheel, although in a few cases
it has been driven by a chain and sprockets.

Live rear axles are divided into a number of types, or classes,
depending on the arrangement of the axle bearings and on the
method of connecting the road wheels to the axle shaft. These
classes are plain live rear axles, semifloaiing rear axles, three-
quarter-floating rear axles, and full-floating rear axles,

26. Plain Live Rear Axles. — ^The first rear axle in gen-
eral use was of the plain live-axle type and was driven by a chain
and sprocket wheels. In this type, each part of the two-piece
axle shaft is supported directly by two bearings, which are
motmted between the axle shaft and the axle tube. Besides
driving the rear wheels, the rotating axle shaft must carry the
weight that comes on the rear axle. Chain-driven axles of
this type are obsolete, practically all the plain live rear axles
now employed being driven by a propeller shaft.

27. An example of a shaft-driven plain live rear axle is
presented in Fig. 21, which illustrates the axle used on the
Ford, model T, automobile, (a) being an external view and
(fc) a cross-sectional view; the two views are lettered the same,
as far as possible, but are drawn to different scales. The
cross-sectional view (fc) shows part of the axle housing a cut
away, exposing to view the axle shaft 6, V and the differential c.

Digitized by

Google

Digitized by

Google

[LES § 1

3 b and b\ which are
ear d being keyed to
)'. Each part of the
/ and g. The road
axle shaft, which is
e is driven from the
h drives the differen-
road wheels, through
ing gear /.

d g is shown in detail
s d made up of bars
lical spring is made.

f two rings a, which
5 b and contain pro-
sing e is placed inside

the Ford differential

t^ — , „ „ w« 1 at a higher rate of,

speed than the other. In this illustration, part of the housing a
is cut away so as to show the gears, and the different parts are
lettered the same as in Fig. 21. On referring to Fig. 23, it
will be seen that the differential consists, in part, of the inner
housing, or casing, k, to which is fastened the bevel dri\dng
gear ;. Three small bevel pinions /, which are fitted to the

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 75

inner housing k and are free to ttim on their own axes, mesh
with the gears d and e, which are keyed to the halves of the
axle shaft. When the automobile is being propelled by the
engine, the pinion i on the propeller shaft turns the inner hous-
ing k by means of the bevel driving gear /. The housing k
carries the small pinions / bodily around with it, and these
pinions, in turn, rotate the gears d and e and thus cause the
axle shaft and the rear wheels to turn. When the automobile
is traveling straight ahead, the gears d and e rotate at the same
speed because the road wheels rotate at the same speed; hence,

Pig. 23

the pinions / do not turn on their own axes, but remain sta-
tionary with respect to the housing k^ simply forming a con-
nection between the housing and the gears d and e. However,
when the automobile turns a comer, or goes around a curve,
the rotation of one rear wheel is resisted more than that of
the other, or, in other words, the inner rear wheel is held back
and does not travel so fast as the outer one, so that the gears d
and e must be allowed to turn at different speeds in order that
one of the road wheels will not skid. When this condition
exists, the pinions /, besides being carried around bodily by
the housing k, turn on their own axes, and thus permit one of
the gears d and e to rotate more slowly than the other and
allow the road wheels to travel at different rates of speed and
' at the same time receive power from the engine.

Digitized by

Google

76 GASOLINE AUTOMOBILES § 1

The meshing of the bevel driving pinion i, Fig. 23, with the
driving bevel gear / tends to thrust the whole differential-
gear assembly sidewise; this tendency is resisted, however,
by a special thrust bearing, which must be provided in all rear
axles employing the bevel-gear drive.

The differential just explained is known as a bevel-gear dif-
feretUial, because the gears inside of the inner housing are
bevel gears. On some automobiles a spur-gear differential
is used. This kind of differential is constructed on the same
principle as the bevel-gear differential, except that spur gears
instead of bevel gears are employed inside the housing.

29. Semifloating Rear Axles. — ^The semifloating rear
axle differs from the plain live rear axle in that the inner ends

Fig. 24

of the axle shaft are supported, that is, have a bearing, in the
differential housing instead of in the axle housing. The axle
shaft, at its outer ends, just as in the plain live axle, rotates
directly in bearings fitted to the axle tube. The inner housing
of the differential rotates on bearings that are motinted between
hubs on each side of the differential housing and the outer or
stationary axle housing. The axle shaft passes freely through
the hubs of the housing, so that it is relieved of the weight of
the differential, and its inner ends are subject chiefly to the
driving stress, the axle tube taking part of the weight of the

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 77

autxttnobile. In this type of axle, the wheels are keyed or
other wise fastened to the outer ends of the axle shaft, just as
in the plain live rear axle.

Owing to the fact that the inner ends of the axle shaft do
not support the differential assembly, and hence are not sub-
ject to as severe bending stresses as those of the plain axle,
these ends of the axle are said to float, whence the name semi-
floating axle is derived.

30. An example of a semifloating rear axle is that used on
the Pierce-Arrow automobile. This axle is illustrated in Pigs. 24
and 25. Pig. 24, which is a perspective view, shows the rear-
axle construction and part of the automobile frame, and Pig. 25,
which is a cross-sectional view of the same axle, shows the axle
housing and differential cut in half, thus exposing to view the
axle shaft a. The same parts in both illustrations are lettered
alike as far as possible. In Pig. 24, the end of the axle shaft
upon which the road wheel is fitted is shown at a; the axle
tube b surrounds the shaft and carries the rear springs, which
are of the three-quarter-elliptic type. The outer differential
housing is shown at c. The brake dnun d is bolted to the wheel
and, when assembled, it is located between the brake bands e
and /, which may be applied and released by the driver either
by means of a hand lever or by a pedal.

31. On referring to Pig. 25, which shows the inside con-
struction of the axle, it will be seen that the axle shaft a is sup-
ported at its outer ends by the bearings g mounted inside of
the axle tube 6, and at the differential by the hubs of the gears h
and h\ into which its inner ends extend and are keyed. The
inner differential housing i is carried by the bearings /, which
are mounted in the outer housing c. The thrust bearing k is
supported against a shoulder in the housing c and prevents
endwise motion of the housing i.

The different forms of bearings used in this axle are illus-
trated in Pig. 26. At (a) is shown the bearing used for sup-
porting the outer ends of the axle shaft; this bearing is marked
with the lett^- g in Pig. 25. It is known as a conical-roller
bearing, and by means of the rollers, which are held between

Digitized by

Google

Digitized by VjOOQIC

§ 1 GASOLINE AUTOMOBILES 79

tapered casings, it prevents the shaft from moving endwise.
The outer casing is not shown in this view, in order to more
clearly show the rollers. At (b) is shown an annular ball
bearing of the type used to support the inner diJBferential
housing, as shown at /, Pig. 26. This bearing consists of two
rings a and fe, between which hardened-steel balls c rotate.
The balls are separated by means of cages d. A ball-thrust
bearing like that used at i, Fig. 25, is shown in Fig. 26 (c).

Pic. 28

It is made up of grooved races a and fc, between which the
balls c rotate. This bearing is mounted in the axle by placing
the ring a against the inner differential housing and the ring d
against the stationary housing, in which position it prevents
endwise motion of the differential.

The differential-gear assembly t, Fig. 26, is driven by means
of the large bevel gear I and the bevel driving pinion m. This
differential is of the spur-gear type, being composed of spur
gears so arranged as to allow one of the road wheels to turn
at a higher rate of speed than the other, as, for instance, in
going around a curve, with both wheds receiving power from
the propeller shaft and engine. At n are shown the wheel
hubs together with a part of the spokes o.

In all bevel-gear-drive rear axles, a thrust in a forward direc-
tion is exerted on the shaft that carries the bevel driving pinion.
In the rear axle shown in Fig. 25 this thrust is taken care of by
the annular ball bearing p\ in other rear axles, it is taken care

Digitized by

Google

80 GASOLINE AUTOMOBILES § 1

of by the use of conical roller 'bearings; and in still others, a
separate thrust bearing is fitted to the bevel-pinion driving
shaft.

32. Three-Quarter-Floatiiig Rear Axles. — In what is
known as the three-quarter-floating rear axles, the bearings
at the outer ends are so mounted outside of the axle tube that
the wheels turn on them and the weight of the automobile
and occupants is carried by the axle tube, or housing. The
axle shaft is rigidly attached to the wheels and helps to keep
them in the correct position; but outside of this, broadly speak-
ing, the only stress that comes on it is the driving stress. In
this axle, the driving shaft does not come directly in contact
with any bearing, but is supported at the inner ends by the
differential and at the wheel ends by the wheels, which run on
the axle tube. The construction at the differential is exactly
like that of the semifloating axle.

33. A three-quarter-floating rear axle, such as is used on
the Overland car, is illustrated partly in section and partly
in full view, in Fig. 27. The left half of this illustration shows
that part of the ^e assembly cut in half, exposing to view the
axle shaft and bearings, while the right half shows a top external
view of the other part of the axle. At a is shown one-half of
the axle shaft, which extends into the differential b at the inner
end, and to which the rear-wheel hub c is keyed at the outer
end. The differential is supported by roller bearings of the
coiled roller type, one of which is shown at d, and the wheds
run on the same type of bearings, which are mounted outside
of the axle tube, as at e. The entire weight of the load is
carried by the axle tube /, the shaft a taking the driving
stress and helping to keep the wheels in a vertical position.
The differential is prevented from being forced endwise by
a ball-thrust bearing on each side. One of these bearings
is shown at g, where it fits between the outer differential
housing h and the thrust collar i. The axle is strengthened
by means of a truss rod /, which may be adjusted by the turn-
buckle k. The bolts / are used for fastening the transmission

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 81

casing, which is not
shown, to the outer
diflEerential housing,
and the levers m and n
are used for applying
the brakes through the
rods o and the tubes p.
The grease retainer q
isintheformofaring;
it prevents the oil and
grease from escaping
from the diJBferential,
being held in place by
the spring r.

34. In the Over-
land axle, the shaft a
may be removed by
loosening the screws
of the collar i and
withdrawing the shaft
through the collar.
The differential may
be removed by with-
drawing the halves of
the ^e shaft and
then removing the
bearing caps s, after
which it may be lifted
out bodily. Of course,
before removing the
differential, the out-
side cover-plate, which
is not shown in the
illustration but which
fits on the bearing
surface /, must be
taken off.

222B— 7

Digitized by

Google

82 GASOLINE AUTOMOBILES § 1

35. Full-Floating Rear Axles. — ^The only difference
between a full-floating rear axle and a three-qiiarter-floating
axle is that in the f onner the rear wheels are not rigidly attached
to the axle shaft as in the latter, but are driven from it by means
of a positive, or dog, clutch, or its equivalent. Two bearings
are required at the outer end to support the wheel in an erect
position. In this type of axle, the entire load is carried by the
axle tube, or housing, while the axle shaft simply transmits
the turning power from the differential to the wheels. The
construction at the differential is exactly the same as in the
three-quarter-floating axle or in the semifloating axle.

36. A typical full-floating rear axle, such as is used on the
Stoddard-Dayton car, is shown in Fig. 28. The left half of
the axle and the differential are shown in horizontal section;
that is, they are considered as being cut in half horizontally,
exposing to view the inside construction. The right half of
the illustration is, in part, an external view of that part of the
axle, looked at from the top.

On referring to the sectional view, it will be seen that the
axle shaft a extends from the differential gear 6, in which it
fits, through the axle tube c, without coming in contact with
any bearings, to the dog d, by means of which it is connected
to the wheel hub e. The dog d has cut aroimd its circum-
ference square teeth that mesh with square teeth cut into the
face of the wheel hub, thus insuring a positive drive. The
differential is carried on the conical roller bearings / and g,
which prevent it from moving endwise, and each wheel runs on
two annular ball bearings, as h and i, which are mounted outside
of the axle tube and support the wheel in an erect position.
The differential is of the bevel-gear type and is driven from
the propeller shaft by the pinion / and a large bevel gear k.
The brakes I and m are operated through the rod n and the
tube o.

As shown in the right half of the illustration, the spring
seats p are carried by the axle tube c, which takes the entire
load brought to bear on the rear axle. The propeller shaft q
is encased by a torsion tube r, which helps to overcome the

Digitized by

Google

Digitized by VjOOQ IC

84 GASOLINE AUTOMOBILES § 1

tendency of the axle tube to turn. Oil and grease are pre-
vented from escaping from the differential by the grease rings s.

37. Fig. 29 illustrates a Timken-Detroit full-floating rear

Digitized by

Google

S 1 GASOLINE AUTOMOBILES 85

splines, or keys, that form an integral part of the axle shaft,
and that engage slots in the wheel hub. The main axle housing/
is made of pressed steel and contains two inner reinforcing
sleeves, or tubes, one on each side; each of these helps to carry
the wheel bearings at its outer end. These inner sleeves extend
in beyond the spring seats g, upon which the weight of the car
rests. The inner ends of the axle shaft are shown at A, view (6) .
When assembled, the differential housing i is bolted to the axle
housing at /, so that the differential gears fit inside of the axle
housing and the ends of the axle shafts extend into them from
each side. The cover-plate k is bolted on the rear of the axle,
as shown in (a). The differential gears are operated through
the large bevel driving gear /, which is driven from the pinion

Fig. 30

shaft m by means of a pinion enclosed in the differential hous-
ing i. The truss rod n, located on the tmder part of the axle,
serves to strengthen it, and the rods and levers on the front
of the axle tube are for actuating the brakes, which are located
at d and o. There are two sets of brakes, the one set being
internal expanding brakes, while the other set, shown at d and o,
are external contracting brakes.

In operation, the outer differential housing is partly filled
with oil, as shown at a, Pig. 30, where part of the axle housing
is cut away in order to show the reinforcing sleeve fe, which
extends inwards as far as shown. There is thus formed on
each side of the axle, between the inside of the axle housing
and the outside of each reinforcing sleeve, an oil pocket that
catches oil thrown sidewise whenever the car is turning a

Digitized by

Google

86 GASOLINE AUTOMOBILES $ 1

corner; oil in large quantities is thereby prevented from work-
ing along the axle shaft into the wheel hubs and thence into
the brakes, where it would ereatlv reduce their efficiency.

ead again, oil in the
er differential housing.

LKles. — ^All the rear
fm the propeller shaft
f the shaft and a large
rential. Another form
of drive that is used
to some ejctent is the
worm-gear drive,
in which the axle
shaft is driven by
means of a worm on
the end of the pro-
peller shaft, and a
worm-wheel on the
differential. The
worm meshes with
the worm-wheel and
turns the differential,
just as the bevel
pinion and gear do in
the more ordinary
form of axle. The
d on any type of rear
rive.

^1 is shown in Fig. 31,
nplete differential-gear
assembly ot a imucen-uavia tJrown rear axle removed from
the axle housing. The worm a is integral with the shaft 6,
and its teeth mesh with the teeth on the wheel c. The teeth
on the wheel are made concave, as shown, so that they make
contact over their entire width with the teeth on the worm.
In the example illustrated, the worm is located on top of the
wheel, but worm-drive rear axles are also built with the worm

Digitized by

Google

Digitized by

Google

88 GASOLINE AUTOMOBILES § 1

underneath. With the type of construction last named, the
worm may run in a bath of oil. In the illustration, one part
of the diflEerential housing is shown at d; a hub formed thereon
carries the roller bearing e.

Lxle is illustrated in Pig. 32,
rt sectional view of the axle
Jail Bearing Company. In
5 top, a part of the housing
loved in order to show the
the wheel-hub; in view (6),
the outside of the axle is
seen from the front end
of the automobile. The
axle is of the full floating
type and in all respects,
except the method of
driving, is similar to the
full-floating rear axles pre-
viously described; there-
fore, only the drive mecha-
nism proper will be dealt
with here. As far as pos-
iews are lettered the same,
ial a is enclosed in the outer
[so encloses the axle shaft c.
is bolted a worm-wheel e,
■m located beneath the axle
le worm is integral with the
le teeth on the worm-wheel,
Irives the wheel e, and con-
5s. The shaft g is connected
e is installed in the car.

:he worm-wheel ^, together
oved from the axle. These
5 bolts h, Fig. 32, and loosen-
t secure the worm-wheel to
town at / in Pig. 33, and the

Digitized by

Google

S 1 GASOLINE AUTOMOBILES 89

end g of the shaft that carries the worm is seen protruding from
the housing /. The end of the axle shaft to which the dif-
ferential gears are fitted .extends into the casing at i, and a
torsion rod can be attached by means of the socket /. The
entire axle can be readily disassembled by simply pulling out
the halves of the axle shaft and lifting out the worm-wheel and
diSerential.

41. Rear- Axle Housings. — ^A rear-axle housing consists,
in part, of an enlarged portion, in the middle of the axle, that
encloses the differential gears, and, in part, of two axle tubes
that surround the two halves of the axle shaft. The enlarged

Pig. 34

part, or differential housing, is sometimes called the bridge,
and the axle tubes are sometimes known as the bridge tubes.
In some rear axles, the outer differential housing and the axle
tubes are separate pieces, the differential housing being either
made in two halves or provided with a large opening to permit
insertion, inspection, and removal of the differential-gear assem-
bly. The outer differential housings are made of cast steel,
cast bronze, cast aluminimi, malleable iron, pressed steel, or
drop forgings, and the tubes are usually made of drawn steel,
although they are sometimes cast. The tubes are fitted to the
outer differential housing in a variety of ways, In some cases.

Digitized by

Google

90 GASOLINE AUTOMOBILES § 1

they are forced into the hubs of the housing and riveted, some-
times they are bolted to the housing, and in still other cases
they are brazed.

The rear-axle housing c shown in Figs. 24 and 25, is made
up of two halves bolted together, the halves of the axle tube b
being forced into the hubs of the housing and riveted. In the
axle shown in Pig. 27, the tubes are fitted to the outer differ-
ential housing in the same manner, but, instead of being divided
into halves, this housing is provided with a large opening on
top for inserting or removing the differential. This opening
is ordinarily closed by a cover-plate, which is bolted on. Prac-
tically the same construction is shown in Pig. 28. The axle
housing illustrated in Pig. 23 is an example of a pressed-steel
differential housing made in halves and riveted to the axle
tube.

42. Pressed-steel rear-axle housings in which the differ-
ential casing and the axle tubes are integral are now in wide
use. Such a housing is illustrated in Pig. 29. The housing /
is pressed in two halves from sheet steel, the top and bottom
halves being welded together by the oxy-acetylene method.
The housing has two large openings in the front and rear for
inserting or cleaning the differential and the driving-gear
assembly.

Another pressed-steel axle housing of the same type is shown
in Pig. 34, which illustrates the rear axle used on one model
of the Marmon automobile. This axle housing is also pressed
from sheet steel in two halves, but these are welded together
so that the seam is in the vertical plane instead of in the hori-
zontal plane, as in the Timken axle. The axle housing shown
in Pig. 34 has, in the rear, a large opening a, that is normally
closed by a cover-plate — ^removed in the illustration. A gear-
carrying plate by shown removed from the differential housing,
carries' the differential-gear assembly c. When the gear-carry-
ing plate b has been removed from the outer differential housing,
the transmission shafts and gears can be pulled out rearwards,
the transmission in this case being incorporated in the rear
axle. The gear-carrying plate b has in it two large holes d

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 91

and € that receive the rear bearings for the transmission shafts
when it is bolted in place. It will be understood that the two
halves of the axle shaft. have to be partly withdrawn if the
differential-gear assembly is to be removed.

43. Tbrslon Rods and Tubes. — ^The rear-axle housing
of a shaft-driven automobile has a tendency to rotate in a direc-
tion opposite that in which the wheels and the axle shaft are
rotating when the engine is driving the car. This is due to the
action of the bevel pinion on the end of the propeller shaft;
it tends to climb up aroimd the large bevel driving gear and to
carry the differential housing and axle tube with it. When the
clutch is thrown out, so that the engine is not driving the car,
and the hub brakes are applied, the wheels tend to drag the

Fic. 35

axle housing arotmd with them, because the brake bands are
supported by the housing; hence, in this case, the axle housing
has a tendency to turn in the same direction that the wheels
are rotating. In order to overcome the tendency of the rear-
axle housing to turn, and to keep it in its correct position,
torsion rods or torsion tubes are often provided.

Torsion rods are solid or hollow rods or channel-section
pressed-steel beams of different design connected at one end
to the differential housing and at the other end to some part
of the automobile frame, thus forming a brace that prevents
the housing from turning. vSometimes the turning effort of the
axle housing is taken by a tube that surrounds the propeller
shaft and is attached at the rear end to the differential casing.
This tube is known as a torsion tube. In other cases, the

Digitized by

Google

GASOLINE AUTOMOBILES

§1

turning eflfort is resisted by the rear springs, which are then
bolted to spring seats that are rigidly fastened to the axle
hotising.

44. A simple method of applying a solid torsion rod is
d in Fig. 35, which shows the propeller shaft a of an
yile and a sectional view of the outer differential hous-
The rear end of the torsion rod c is rigidly attached
axle housing; the forward end is connected to the
of the car by means of a link and pins. The link-
connection allows the axle free play up and down, and
ivards and backwards to some extent, on account of
iction, while at the same time it resists the tendency
Lousing to rotate.

A torsion member composed of two rods arranged
Dim of a triangle, as used on the McCue rear axle, is

Fig. 36

3d in Fig. 36. The rear ends of the hollow rods a are
3 the top and the bottom of the axle housing 6, and the
ds of these rods are joined to a suitable fitting c. This
in turn, is attached by means of a spring connection
ss-member d of the frame of the car. The end of the
; made in the form of an eye, through which the spring
ses; thus, the fitting is cushioned between the springs e,
•e suspended from d, and the shocks coming on'the frame
ir are by this means greatly reduced.

Fig. 37 shows the torsion tube used in one model of

heson car. The propeller shaft a rotates in the tube 6,

5 rigidly attached at its rear end to the transmission

case c. In this instance, the transmission is located at the

rear axle, so that its casing is an extension of the differential

Digitized by

Google

GASOLINE AUTOMOBILES

housing; fixing the torsion tube to the casing has the same
effect as fixing it to the axle housing. The axle tube is at-
tached to the transmission case by means of a sleeve, or socket,
d, which is bolted to the casing and in which the end of the
tube is held by the screws e. The forward end of the tube is
carried in the casing/, to which it is fastened by the screws g;
this casing, in turn, is supported on a roller bearing moimted
on the propeller shaft. Any tendency of the rear-axle housing
to turn is thus prevented by the torsion tube. The propeller
shaft is driven from the engine through the shaft h,

47. Radius Rods. — In the strict sense, radius rods are
rods attached at one end to the rear axle of an automobile
and at the other end to the frame for the purpose of keeping
the axle in alinement with the remainder of the car. These

Fic. 37

rods, one on each side of the frame of the car, are usually pro-
vided with two yoke ends, one of which is pinned to a lug car-
ried by the spring-seat forging or by a special fitjing on the
axle tube, and the other to a lug on the frame, thereby per-
mitting the axle to move freely up and down, but maintaining
equal distances to the ends of the axle. In chain-driven cars
equipped with swivel spring seats, the radius rods also serve
as take-up rods for adjusting the distance between the engine
sprocket and the differential sprocket. These rods are usually
equipped with ttunbuckles that permit of taking up any undue
slack caused by wear. When tumbuckles are not used, the
yoke ends are made longer and are threaded, so that the chain
tension may be varied by screwing or tmscrewing them.

48. The radius rods used on the Stoddard Dayton, "Say-
brook" model, automobile are shown at a and 6, Fig. 38, which

Digitized by

Google

94 GASOLINE AUTOMOBILES § 1

is an illustration of the rear half of the chassis of this car. Each
rod is attached at its forward end to a bracket c on the frame d,
and at its rear end to a fitting on the axle tube e. The radius
rods here shown are fitted with a imiversal joint / at each end,
which joints prevent the rods from being strained by any move-
ment of the axle. The axle may move freely up or down, but
both ends of the axle are always confined lengthwise of the
frame. The method of attaching the three-quarter-elliptic
springs is also shown in this illustration. The lower half g
of each spring is shackled at its forward end by means of links
and bolts to a hanger h that is fitted to the frame. The rear
end of the lower half is shackled to the upper quarter f , which

Pig. 38

is clamped to the rear cross-member of the frame at /. Other
parts of the chassis shown in Fig. 38 are the gasoline tank k,
the wheel bearing /, the hub brakes m, and the brake rods n.

49. With some shaft-driven cars, the torsion tube that
surrounds the propeller shaft, or the torsion rod used with the
rear axle, not only serves to take care of the torsional stress
produced by the driving pinion, but takes the place of the
radius rods used on other cars. Sometimes neither a torsion
rod nor radius rods are used, the driving stress being taken
by the springs alone, one end of which, usually the forward end,
is then hinged to the frame in the case of half-elliptic springs.
In the case of three-quarter-elliptic springs, the front end of

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 96

the lower member is hinged to the frame. With full-elliptic
springs, the upper half is rigidly bolted to the frame and the
lower half to the rear-axle housing; the two halves of the spring
must then be hinged together at least at one end. Whenever
springs serve as raditis rods, which is almost invariably the case
with front axles, the springs must be bolted to spring seats
that are rigidly attached to the axle.

Diagonal brace rods, which are also commonly classed as
radius rods, are used on a niunber of automobiles for the ptir-
pose of tying the rear axle and the torsion tube together. One
of these rods is located on each side of the car, and extends
from the outer end of the axle tube to the forward end of the
propeller-shaft housing, or torsion tube. Such brace rods
usually have yoke ends, and they are attached in the same
manner as the true radius rods just described. This form of

Pig. 39

radius rod is not attached to the frame of the car, so that it
does not take the driving stress; it serves only as a stiffener,
or brace, holding the axle and the torsion tube in their correct
relative positions.

50. I>ead Rear Axles. — Dead rear axles, or axles that are
stationary, are usually forged I-beam sections, and sometimes
they are made with a drop between the spring seats; that is,
the middle part is lower than the ends. Such an axle, as vised
in the Great Chadwick car, is illustrated in Fig. 39. Each of
the spindles a carries two annular ball bearings 6, upon which
the wheels rotate. The parts c, between the spindles and the
spring seats d, provide room for the radius rods and braking
mechanism. The main part e of the axle is dropped below
the spring seats, as shown. Some dead rear axles are made
perfectly straight and of rectangular cross-section, but as a
rule the I-beam section is used.

Digitized by

Google

96 GASOLINE AUTOMOBILES § 1

51. Dead axles are used with only the double-chain type
of drive, in which the reax; wheels are driven from a counter-
shaft by means of side chains. The location of the chain and
sprockets by means of which the wheels are driven is shown in
Fig. 40, which presents a view of the rear of the chassis of a
Chadwick automobile. The upper half a of the chain case
is lifted, exposing to view the chain 6, which passes around
the sprocket c on the end of the countershaft and the sprocket d
on the wheel hub. In this case, the sprocket d forms part of
the brake drum e, which is bolted to the spokes of the wheel

Fig. 40

by the bolts/. On the inside of the chain case, and forming a
part of it, is the adjustable radius rod g, by means of which
the distance between the sprockets c and d can be adjusted,
or changed, to allow for wear on the diain. The chain case,
when closed, serves to protect the chain from dust and dirt.

52. Automobile Clialns. — The automobile chains now
in use for driving the rear wheels of a car are of the roller type
exclusively. This type is so named because it is provided
with rollers, which rotate on pins connecting the side links.
All roller chains consist of these essential parts, although there

Digitized by

Google

§ 1 , GASOLINE AUTOMOBILES 97

are several different methods of attaching the side links to the
pins.

53. A Baldwin detachable roller chain, or one that
can be separated at each link, is iUnstrated in Pig. 41. The
pins a are formed with a head on one side of the chain, and
on the other side they are provided with special dips that hold

m>z

Pig. 41

the links in place. The rollers b rotate on bushings c that
sumoimd the pins a. At one end of each pin are milled two
slots d, into which, after the side link e is slipped on, the clips,
or fasteners, / are forced and closed by a pair of flat-nose pliers.
These clips may be removed by means of a screw-driver or
with a special tool provided by the chain manufacturer. The
pins, or studs are knurled at the neck where they pass through
the links, into which they are forced under pressure.

54. A form of roller chain that can be detached at only
one link, called the master linky or connecting link, is illustrated
in Fig. 42. This chain, like the one shown in Fig. 41, is made up
of rollers a that run on bushings b supported by pins c. In

Fig. 42

this case, however, the pins are riveted on both sides of the chain,
so that the side links cannot be removed except at the master
link. In the illustration, the master link is shown at the right-
hand end of the piece of chain. Instead of nmning on rivets,

222B'-«

Digitized by

Google

98 GASOLINE AUTOMOBILES § ]

the rollers e of this link turn on bolts / that are fitted with
nuts g and cotter pins fe, so that the chain can be separated at
this point by removing the bolts. Each chain is provided with
aster link, or connecting link.
1 illustrated in Fig. 42 is known to the trade as the
cliain. There are several other makes of detach-
1 as riveted, roller chains on the n:iarket; these are
lown to the trade by the names of their makers,
tiey embody the same general principle they natur-
xmewhat in their details.

SPRINGS ANB FRAMES

AUTOMOBILE SPRINGS

tomobile springs, which are used for support-
le and body of an automobUe on its axles, are made
and comparatively thin and narrow curved steel
aves, of different lengths. These leaves are usually
3r by a bolt at the center, although in some springs
eliminated and cUps are used entirely. The shorter
usually prevented from moving sidewise by small
r ends, by projections of one leaf entering corre-
spressions of the next leaf, or by cUps that pass
n. Springs are assembled in a ntmiber of different
are named according to the form in which they are

. 43 shows each of the different types of automobile
iitline, as well as the way in which the parts are held

lllptlc spring, or, simply, an elliptic spring, is
h the leaves are bent, or arched, so as to take the
jllipse. Fig. 43 (a) shows a common form of elliptic
is composed of an upper and a lower half joined at
rith bolts. This spring is sometimes known as the
elliptic spring, because the bolts are commonly
a head resembling a button.

Digitized by

Google

Pig. 43

Digitized by

Google

100 GASOLINE AUTOMOBILES § 1

A single-scroll elliptic spring is illustrated in view (6).
This spring differs from the common elliptic spring in that its
upper half is provided with a scroll at one end and is joined
to the lower half at this end by a shackle and at the other end
by a bolt, instead of having bolts at both ends. The scroll ^d
is curved down around the lower half and is attached to it hy
links and tjolts, forming the shackle.

A double-scroll elliptic spring, as shown in view (c),
is shackled at both ends, the upper half being provided with
two scrolls.

The different types of elliptic springs so far described are used
as front springs in some cars and as rear springs in others,
although they are not employed very extensively in either case.

A three-qUarter-elllptic spring is one composed of the
bottom part and one-half of the top part of a full elliptic spring,
joined either by a bolt or by a shackle. Such a spring, in which
the upper qtiarter is scrolled and shackled to the lower half,
is shown in view (d). This type of spring is used more than
any other as a rear spring on pleasure cars.

A lialf-elliptic spring is simply half of a full-elliptic spring.
An ordinary spring of this type is shown in view (e) . A specially
constructed half-elliptic spring, known as the Titanic spring,
which does not have a bolt at the center, is shown in view (0-
The leaves of this spring are arched so as to form a himip at
the middle, and are clamped over a filler that maintains this
himip. Greater strength is claimed for this spring in the cen-
ter, on accoimt of doing away with the bolt hole that is neces-
sary in the ordinary spring. The half-elliptic spring, or semi-
elliptic spring, as it is sometimes called, is used largely on pleas-
ure automobiles for supporting the front end of the frame; in
a few cases, it is used for supporting the rear end.

A cross-spring is a spring that runs crosswise on the car,
and therein it differs from the springs previously described,
which are arranged lengthwise with the frame. The cross-
spring resembles an inverted semi-elliptic spring, as will be seen
on referring to view (g), which shows the rear cross-spring of
the model T, Ford car. When in place on the car, it is shackled
to lugs on the axle at both ends and supports the load at its

Digitized by

Google

§ 1 GASOLINE AUTOMOBILES 101

center. Cross-springs are employed only on the lighter class
of automobiles.

In view (h) is shown a platform spring, of which the side
members are half -elliptic springs shackled to the cross-member,
and the rear member is an inverted half-eUiptic spring. This
spring assembly is used as a rear spring on a few pleasure cars,
and it is attached to the frame at the forward ends of the side
members and at the center of the cross-spring.

What is known as a cantilever spring is shown in view (i).
It consists of an inverted and very flat semielliptic spring
shackled at its rear end to the rear axle and at its front end
to the frame, and pivoted at its middle to the frame. The
spring may also be attached to the axle by means of a roller
connection, which allows a free backward-and-forward motion.
When supported in this manner, it extends imdameath the
axle. A cantilever spring may also consist of a quarter-elliptic
spring, having its big end rigidly attached to the frame and
its small end shackled to the axle. . A cantilever spring is used
as a rear spring wherever employed, but it is found at present
on a comparatively small number of automobiles, among which
may be mentioned the King and the Edwards-Knight cars.

57. After a spring has been compressed, the following
upward movement, or recoUy tends to cause separation of its
leaves, which separation may result in their breakage. This
fact -is especially true of the master leaf, which is that leaf on
the ends of which are formed the eyes for attaching it to the
frame of the car, to the shackles, or to the other part of the spring
in case of other than the half-eUiptic spring. To reduce this
danger of spring breakage through recoil, many springs are
now fitted with recoil clipSy which are narrow clips that surroimd
several spring leaves and the master leaf, and that permit
free sliding of the leaves on each other while restraining their
separation. Such recoil dips are shown at a, Fig. 43 (c), (d),
(0, (g), and (A).

Digitized by

Google

102 GASOLINE AUTOMOBILES § 1

SHOCK ABSOHBESEUS

58. Types of Sliock Absorbers. — Devices that are used
to modify the action of automobile springs and thus prevent
excessive vibration of the body of the car while passing over
rough roads are called sliock absorbers. These devices are
attached to the frame and the springs or axles, so that they
offer resistance to the action of the springs and tend to do
away with any jar when the springs are suddenly compressed,
or when they recoil. There are three types of shock absorb-
ers, depending on the method used to obtain the required
resistance: (1) those which depend on the frictional resist-
ance of two or more surfaces in contact; (2) those which depend
on restricting the flow of a fluid; and (3) those which depend
on the action of some kind of supplementary springs.

59. Friction Shock Absorbers. — One of the most widely
used friction shock absorber is the Truffault-Hartford device,
which is shown in Fig. 44 (a). It is made up of circular disks.
Some of these move with the arm a, which is attached to the
frame c in the manner shown, and some with the arm 6, which
is attached to a special spring clip d or to a lug carried on a
plate held in place by both spring clips. The frictional ten-
sion on the disks may be adjusted by loosening or tightening
the nut e. This nut presses against a five-fingered bearing
plate / that carries a pointer g for indicating the degree of pres-
sure on the outer disk. The action of the springs is modified
by the frictional resistance of the disks when the arms a and b
move toward each other, as when the springs are compressed,-
or away from each other when the springs recoil.

60. The device shown in Fig. 44 (6) is called the Gabriel
rebound snubber, or cbeck, because it has no effect on the
compression of the spring, but serves merely to check its move-
ment on the recoil. It consists of the fabric belting a that is
faced with a flexible brass friction band b and is wound about
a base consisting of a fixed half c and a movable half d; the
two halves of the base are separated by the coil spring e.
The telescopic connection / permits the movement of the

Digitized by

Google

GASOLINE AUTOMOBILES

103

half d of the base, so that when the springs rebound, the coils
erf belting tighten and unwind, thus creating a friction on the
brass band and gradually absorbing the shock of the recoil.
As the springs compress
again and allow the {<o;

fiame and axle to move
toward each other, the
coil spring e expands and
takes up the slack in the
belting. When in use,
the stationary half e of
the base is fixed to the
frame of the car and the
piece of belting is at-
tached to the axle, as
shown.

61. Fluid Sliock
Absorbers. — In one

type of the so-called fluid
shock absorber, a piston
reciprocates in a cylinder
in which there are no
valves. A small by-pass
is provided in the side
of the cylinder, so that
the frictional resistance
to the passage of air
through the by-pass from
one side of the piston to
the other is such that the
passengers practically
ride on an air cushion.
In another fluid shock
absorber, glycerine is placed in a vertically arranged cylinder
that is connected to the axle, a piston that moves inside the
cylinder being connected to the frame. Under the alternate
compression and expansion of the springs, the glycerine is

Pic. 44

Digitized by

Google

104 GASOLINE AUTOMOBILES § 1

forced through small passages from one side of the piston to
the other. The hollow piston rod is provided with a regulating

valve by which the modifying effect of
^ the shock absorber may be varied at

will.

62. Spring Sliock Absorbers.

Several devices that absorb road shocks
through the action of coiled-steel
(a) springs are shown in Fig. 45.

In (a) is shown the Sager equal-
izing springy which is a simple coiled
spring attached to the frame and to
the axle, so as to be in compression
during the descent of the body and in
tension during its rise, and thus
modify the spring action in both direc-
tions.

View (b) shows the J. W. shock
absorber applied to a three-quarter
elliptic spring. Each of the tubes a
contain a helical spring 6, which is
held against the upper end of the tube
by means of a bolt c having the shape
W of an inverted U. The lower end of

the spring b presses against
a plate that fits inside of the
tube and is supported by
the nuts d on the end of the
I bolt. The plate can slide
up or down inside of the
tube as the spring is com-
pressed or extended. The
tubes are attached to the
top member e of the spring,

and the inverted U bolt is

^^^ carried by the bottom mem-

^'^' *^ ber /, so that as the body

Digitized by

Google

S 1 GASOLINE AUTOMOBILES 105

of the car descends the shock absorber springs are first com-
pressed, thtis modifying the action of the main springs. When
applied to a car eqtdpped with semi-elliptic springs, one part
of the absorber is attached to the frame and the other part to
the spring.

The shock absorber shown at (c) is a recoil checking device.
It consists of a curved spring fastened at one end to the axle,
and attached at the other end to the frame by means of a strap.
This kind of device is designed to eliminate upthrow of the
body in passing over obstructions in the road, and to prevent
breakage of the springs by absorbing the recoil.

63. The rebound of the spring is sometimes limited by
making use of reversely curved leaves on top of the main leaf,
as is shown in Fig. 46. The reverse leaves a and b tend to
counteract the reboimd of the spring and thus prevent it from
breaking. Before assembling, the reverse leaves have the

Pig. 46

form indicatec^ by the dotted lines, so that when they are
forced into place, and the bolt c is appUed, they tend to
straighten out the spring and in reality to weaken it. But
when the spring reboimds after being compressed, these short
leaves prevent it from coming back to its original position
with too sudden a shock. It is thus seen that this form of
shock absorber, like those illustrated in Fig. 44 (6) and Fig. 45
(a), only limits the movement of the spring on the recoil.

AUTOMOBILB FRAMES

64. Types of Frames. — ^The frame is that part of the
automobile that supports the body and machinery of the car;
the frame rests on the springs. With r^ard to the material
of which they are built, frames used on pleasure cars are of
two kinds, namely, pressed-steel frames and wooden frames.

Digitized by

Google

106 GASOLINE AUTOMOBILES § 1

Pressed-steel frames are
used almost exclusively,
wooden frames being used
on only a few cars. Where
wooden frames are used,
they are either armored
with steel plates or lami-
nated, that is, made up of
several layers or lamina-
tions. A frame made of
wooden sills is used on the
Franklin automobile, which
offers the best illustration
of this type. On this car,
the main frame is made of
three laminations of second-
growth white ash with a
thin strip of wood placed on
^ the top of the sills to pre-
I vent water from getting
between the laminations,
the whole being glued to-
gether.

65. Pressed-steel
nrames. — ^P r essed-steel
frames are made up of parts
pressed, or formed, to the
required shape in hydraulic
presses. The longitudinal
sills, or side rails, running
lengthwise on the car, are
practically always made in
channel sections, and the
cross-members, running
from one side to the other,
are largely made in the
same shapes.

Digitized by

Google

S 1 GASOLINE AUTOMOBILES 107

A perspective view of the pressed-sted frame used on one
model of the Packard car is shown in Fig. 47. Besides the
various brackets that are riveted to the frame, the front and
rear springs and the front axle are shown in place, illustrating
how those parts are attached to the sills. The channel-shaped
side rails, or sills, a and b are connected by the four cross-
members c, d, e, and /, which are also formed in channel sec-
tions. The front springs g are hinged to the side rails at the
forward end by the bolts h, and are shackled at the rear by the
links t and bolts ; and k. These springs are held in place on
the front axle / by the spring clips w.

The lower halves n of the rear springs are. shackled to the
side rails at the forward end, and to the top quarter o of the
springs at the rear. These springs are attach^ to the frame
by the clips p. The radius rods g, with brackets r for attaching
them to the rear axle, are shown in place. Brackets s support
the running boards, and brackets t hold the toe board in place;
the lever u is part of the reversiog mechanism.

While all pressed-steel automobile frames are not built
exactly alike, the forgoing will serve to illustrate how the parts
are arranged and attached on a typical frame. It is to be noted
that this frame is mounted on top of the springs and above
the axles. This is the usual method of mounting an automo-
bile frame, and is employed on the great majority of cars.

In many cars, the frame is raised over the rear axle, as shown
in Fig. 47, in order to give clearance over the rear axle and to
permit the body to be brought lower to the ground than is
possible with a straight frame; such a frame is said to be upswept,
or kicked up. When it is offset vertically in the same manner
at the front, the frame is spoken of as a double kick-up frame.
Many frames are narrowed at the front end in order to give a
larger turning radius to the front wheels, which means a shorter
turning radius for the car; such a frame is said to be inswept
at the front. The frame shown in Fig. 47 has this construction.

66« XJndersltiiig Frames. — ^An underslung frame is

a frame that is located underneath the axles and suspended
from the springs. This type of frame gives a low center of

Digitized by

Google

108 GASOLINE AUTOMOBILES § 1

gravity to the car, but requires the use of larger wheels than
can be used on cars having the frame mounted on top of the
springs and axles.

tne subtrame is generally made ot pressed-steel shapes ot chan-
nel cross-section, although tubular subframe members are
sometimes foimd

Digitized by

Google

GASOLINE AUTOMOBILE ENGINES

PART 1

PRINCIPLES OF OPERATION

FOUR-CYCLE PRINCIPLE

DEFINITIONS AND NAMES OF PARTS

1. An internal-combustion engine is an engine in which
power is generated by burning within the cylinder, a combus-
tible mixture of air and gasoline, air and kerosene, or air and
any other liquid fuel. The burning of the fuel results in the
production of gases of high temperature and pressure, which
act directly on a piston that moves back and forth in a cylin-
der to which the air and fuel are admitted and from which the
burned gases are discharged by means of suitable valves. The
required mechanical work is done by the piston through the
proper mechanism. ^Internal-combustion engines are classified
as single-acting engines and double-acting engines, depending on
their construction and operation. Engines in which the cylin-
der is so constructed that gas is admitted to only one end and
burned on only one side of the piston are single-acting
engines, because the expanding gases force the piston in but
one direction; engines in which gases are admitted to each end
of the cylinder alternately, and burned first on one side of the
piston and then on thp other, forcing it first in one direction
and then in the other, are double-acting engines. All gaso-
line automobiles now in use are driven by sonje type of the

conrmaHTSD by intkrnationai. tkxtbook company, all riohts rmkrvkd

Digitized by

Google

Digitized by

Google

§ 2 GASOLINE AUTOMOBILE ENGINES 3

single-acting intemal-combiistion engine. Double-acting inter-
nal-combustion engines have never proved successful as auto-
mobile engines, but are used to some extent as stationary
engines, being sometimes employed in power plants where gas
instead of gasoline is used as fuel.

2. An external view of a typical modem poppet-valve gaso-
line automobile engine is presented in Fig. 1, which shows the
left side of one model of the Pierce-Arrow six-cylinder engine.
The cylinders are cast in pairs — ^that is, there are two cylinders
in each of the castings, or blocks, a. The cylinders are ver-
tically arranged on the crank-case 6, which supports them and
which contains a shaft c, called a crank-shaft, extending its
entire length. The crank-shaft, being rapidly rotated by the
up-and-down movement of the pistons in the cylinders, through
suitable cranks and connecting-rods, imparts a rotary motion
to the driving mechanism of the automobile through a clutch
located at the rear of the engine inside of the flywheel d. The
combustible mixture enters the cylinders at the right side of
the engine, and the btuned gases resulting from the explosions
escape through the outlet manifold e. The piping / is for the
purpose of circulating water through jacket spaces surroimd-
ing the cylinders and thus cooling them and preventing them
from being burned or otherwise injured by the heat due to the
explosions. The /an g, located at the forward end of the engine,
also belongs to the cooling system, its purpose being to draw
air through a radiator, which is used to cool the circulating
water. Other important parts shown are the oil pump h, with
the necessary piping, for lubricating the engine; the water
pump i, for circulating the cooling water; an electric generator k,
for supplying electric current for lighting purposes as well as
for ignition; the wires I, for carrying electric current for igniting
the combustible mixture in the cylinders ; and the valve springs m,
used for closing the valves, which permit the gases to enter
and escape from the cylinders. The engine is supported in
the frame of the car at four points by means of the supports n,
two of which are located on each side. These supports are
secured to the side members of the frame.

Digitized by

Google

Pig. 2

Digitized by VjOOQ IC

§ 2 GASOLINE AUTOMOBILE ENGINES 5

3. A cross-sectional view of the Pierce-Arrow six-cylinder
engine showing the arrangement of the parts inside of one of
the cylinders is seen in Fig. 2. This illustration shows one of
the cylinders cut in half crosswise and viewed from the forward
end of the engine. The oil pump, water pump, and other
accessories are omitted in order to simplify tJie view.

The piston a is free to move up and down within the hollow,
or bore, of the vertical cylinder b. The piston is coimected to
the crank c by means of the connecting-rod d, which is attached
at its upper end to the piston pin e and at its lower end to the
crank-pin J, so that an up-and-down motion of the piston causes
the crank to rotate. The crank-shaft g, being integral with the
cranks, also rotates, and through it the driving mechanism
of the car is caused to turn. The crank-shaft is carried in
bearings supported by the crank-case h.

At i is seen an opening called the inlet port, through which
the mixture of gasoline vapor and air enters the cylinders;
and at / is the exhaust port, through which the burned gases,
or products of combustion, are expeUed. These openings
are fitted with valves k and /, called the inlet valve and the exhaust
valve, respectively, by means of which the ports may be closed.
The wall of the port on which the valve rests when in the closed
position is known as the valve seat. The valves are operated
by means of cams m and push rods n. The cams are carried
on cam-shafts o, which are rotated by means of gears from the
crank-shaft, and, as the cams revolve, the lobes, or raised por-
tions, strike on and raise the push rods, which in turn lift the
valves. This cam-shaft always rotates at one-half the speed
of the crank-shaft; in other words, for every two revolutions
of the crank-shaft the cam-shaft ntiakes one revolution. It
will be noticed that in the illustration the inlet valve cam
is turned so that its lobe is directly underneath the push rod,
in which position the inlet valve is raised and the inlet port
opened; the lobe of the exhaust valve cam is at one side of
the push rod, in which position the exhaust valve remains
on its seat in a closed position. The push rods are provided
at the bottom with rollers on which the cams strike. The
valves are held in place by the guides p in which the valve

222B— 9

Digitized by

Google

GASOLINE AUTOMOBILE ENGINES § 2

5 and by the springs q. The springs are constantly

i so that they push downwards on the caps r and

alves closed except when the lobes of the cams strike

xis.

nder head is seen at s and between it and the valves

:^ t, called the combustion chamber, or the compres-

because it is in this space that the burning, or com-
f the fuel, takes place. In the cylinder head are
i V, which can be taken out when the valves are to be
)r the cylinder cleaned. The spark plugs w are
to the combustion chamber for the purpose of pro-
;tric sparks to ignite the fuel,'and the priming valve x

means for pouring extra fuel into the cylinder when
or for pouring kerosene in to clean the piston face
•walk.

> end of the cylinder that is attached to the crank-
led the crank end, and the other end is called the

The movement of the piston from the head end
ik end is called the forward, or outward, stroke; the

in the opposite direction is called the return, or
oke,

le piston has reached the end of either stroke, the
-rod and crank are in a straight line, and the pres-
5 gases on the piston is transmitted directly to the

bearings, none of it being used to turn the crank,
crank occupies this position it is said to be on its
ter. There are two dead-center jx^sitions, corre-
;o the two extreme jx^sitions of the piston. When
is at the extreme bottom end of its stroke, the crank
iter, or lower, dead center; and when the piston is at
le top end of its stroke, the crank is on its inner,
^£ad center.

\ cliarge is a mixture of fuel and air taken in at
5 of the engine. It varies according to the con-
operation, and may sometimes be sufficient to fill
ler completely at atmospheric pressing, while at

Digitized by

Google

§2 GASOLINE AUTOMOBILE ENGINES 7

other times it may be reduced. The proportions of fuel and
air may also vary from time to time.

The burned gases, which are expelled from the engine after
having performed the work required, are known as the exhaust
gases, or, simply, the exhaust. These gases are waste products
and are allowed to escape into the atmosphere.

6. Gasoline automobile engines are either vertical or hori-
zontal, depending on the manner in which the cylinders are
arranged. Engines having their cylinders arranged ver-
tically, like that illustrated in Figs. 1 and 2, are vertical
engines ; engines having their cylinders arranged horizontally
are horizontal engines. Practically all engines now used
to propel gasoline pleasure automobiles are of the vertical type.

OASOLINE-ENOINE CTCLB

7. A cycle is any chain, or series, of events, or happenings,
occurring over and over in the same order. As applied to a
gasoline engine, the term cycle refers to the operations, or
events, that take place within the cylinder from one explosion
to the next, and by means of which the fresh charge is drawn
into the combustion chamber and exploded and the exhaust
gases expelled. These events always occur in the same order
and are repeated after each explosion. The cycle on which
an internal-combustion engine operates is one of the distin-
guishing features of different types.

8. The modem cycle of gasoline engines is known as the
Beau de Hoclias cycle, after the name of the inventor, and
more commonly as the Otto cycle, after the name of the engi-
neer who carried out its early commercial application. This
cycle, in its broad and strictly scientific meaning, does not take
into consideration the method of getting the charge of com-
bustible mixture into the cylinder nor that of expelling the hot
burned gases.

The steps of the cycle in the engine of Fig. 2 are as follows:
Suppose that, at the beginning of operations, the valves are
closed, that the piston is at its position farthest out toward
the crank-shaft, and that the cylinder is filled with a com-

Digitized by

Google

8 GASOLINE AUTOMOBILE ENGINES § 2

bustible mixture at atmospheric pressure. By forcing the
piston inwards to the completion of the inward stroke, the
charge will be compressed into the compression space, or com-
bustion space. Now by igniting the compressed charge,
the pressure will be increased still more by the heat of
combustion. The pressure tends to drive the piston out-
wards, and as soon as the rotating crank-shaft has made the
angle between the connecting-rod and crank suflSciently great,
the pressure of the hot gases against the piston face will drive
the crank-shaft. The biimed gases expand to fiU the increas-
ing volume of the cylinder as the piston moves outwards and
the pressure decreases. At the completion of the outward
stroke, the exhaust valve is opened and the hot biimed gases
escape by expansion tmtil the pressure falls to that of the
atmosphere. This completes the Otto heat cycle.

9. The method of expelling the burned gases that remain
in the cylinder at atmospheric pressure and of taking in a fresh
charge of combustible mixture has not yet been considered.
This is accomplished in two distinct ways, which are the foim-
dation for the commercial names, four cyck and two cycle, as
applied to automobile engines.

10. A four-cycle engine is one in which fovir complete
strokes of the piston are required to complete the cycle. In
this engine the burned gases remaining in the cylinder after
the exhaust valve has been opened and part of the hot gases
removed by expansion are expelled in part by a separate inward
stroke of the piston, and a fresh charge is drawn into the cylin-
der through the inlet port by a separate outward stroke. Gen-
erally speaking, one event occurs during each of the four strokes
of this cycle; that is, considering the stroke by which the charge
is drawn into the cyUnder as the first stroke, the mixture is
compressed during the second stroke, burned during the third
stroke, and the exhaust gases are expelled during the fourth
stroke, after which the conditions are the same as at first and
the cycle is complete.

!!• A two-cycle engine is one in which only two strokes
of the piston, corresponding to one revolution of the crank-

Digitized by

Google

§2 GASOLINE AUTOMOBILE ENGINES 9

shaft, are required to complete the cycle. In this cyde an
explosion occurs on each downward stroke of the piston, the
fresh charge being admitted and the exhaust gases expelled
at or near the end of this stroke. Hence, for the same number
of revolutions of the crank^shaft, there are twice as many
explosions in the cylinder of a two-cycle engine as in that of a
four-cycle engine. However, this does not mean that the
power developed by a two-cycle engine is twice as great as that
produced by a four-cycle engine of the same size and speed,
for, on accotmt of the inefficient scavenging, or cleaning, of the
'cylin/ier after the explosion and the lower compression pres-
sure in the two-cycle engine, the explosions are not so power-
ful as in the four-cycle engine. It is generally estimated that
a two-cycle engine of a certain size and speed will develop
about L65 times as much power as a four-cycle engine of the
same size and speed.

12. The two types of internal combustion engines just
defined are sometimes designated by the longer terms four-
stroke OtUhcycle engine and two-stroke Otto-cycle engine to dis-
tinguish them from other engines that operate on cycles that
differ from the Otto. However, since all automobile engines
of the internal-combustion class operate on the Otto cycle, the
terms four-cycle and two-cycle are suflSdently definite in
meaning when limited to this field of application.

13. It has been found that by compressing the charge
before igniting it, a greater amount of power can be obtained
from a given quantity of fuel than by simply burning it at
atmospheric pressure. In other words, the effidency of the
btemal-combustion engine is increased by compressing the
charge before igniting it. Compressing the charge heats it;
hence, on account of the danger of overheating the cylinder
the compression pressure is limited to from 60 to 75 pounds
per square inch, as shown by a pressure gauge. Another
disadvantage of too high a compression is that the bearings
and joints of the moving parts of the engine are liable to give
trouble by knocking or pounding. All internal-combustion
automobile engines compress the charge before igniting it.

Digitized by

Google

10 GASOLINE AUTOMOBILE ENGINES § 2

OPEERATION OF FOUR-CJTCLE ENOINB

14. As already explained, four separate strokes of the
piston, two outwards and two inwards, are required to complete
a cycle in the cylinder of a four-stroke cycle engine. These
four strokes are shown diagrammatically in Fig. 3, which presents
four cross-sectional views, each showing the cylinder a and
crank-case b cut at right angles to the crank-shaft c, exposing
to view the piston d, connecting-rod e, inlet and exhaust valves/
and g, and cams h and i. These views illustrate the various
steps in the operation of the four-cycle type of automobile engine
and the corresponding positions of the valves. The engine
presented in the illustration does not represent any particular
make but shows the principle on which aU f otir-cycle gasoline
engines are operated. If the different events here described
are understood there will be no difficulty in comprehending the
operation of any engine of this type.

15. The first stroke in the operation of the engine is shown
in Fig. 3 (a). During this stroke the piston d, following the
motion of the crank-shaft c, which is being propelled by the
force of the preceding explosion, moves downwards as indicated
by the arrows. At or slightly after the time that the piston
starts on this stroke, the inlet valve / is opened by means of
the cam h. The downward motion of the piston tends to pro-
duce a vacutun in the upper part of the cylinder, so that com-
bustible mixture flows into the cylinder through the inlet port,
as shown by the curved arrows, to fill up this vacuum, or, in
other words, a charge is drawn into the cylinder. At the end
of this stroke, or slightly after, the inlet valve closes. The
exhaust valve g is kept closed during this stroke so that none
of the entering charge can escape through the exhaust port.
Because of the fact that the combustible mixture is drawn into
the cylinder during this stroke, it is usually called the suction
stroke, although it is also variously known as the charging
stroke^ admission stroke, inlet stroke^ and induction stroke.

16. During the second stroke in the cycle of operations, the
piston d, still driven by the crank-shaft c, moves upwards as

Digitized by

Google

Digitized by

Google

:jasoline automobile engines § 2

he arrow in view (b). Both the inlet valve/ and the
ive g are closed dming this stroke, so that the com-
Lture that was drawn into the cylinder on the suction
>w compressed into the small space between the top
n, when it is at tHe top of its stroke, and the cylinder
y thus compressing the charge into a small space
ing it, a greater amount of power can be obtained
jn quantity of fuel as previously explained. About
tiat this stroke, which is called the compression
completed, the charge is ignited by means of an
rk.

e combustible mixture that was drawn into the
the first stroke of the piston and compressed on the
)ke is completely burned during the third stroke,
iston is again on its downward movement, as shown
. The combustion of the charge is so rapid during
as to be practically instantaneous, and is usually
explosion. The pressure in the cylinder, resulting
plosion, drives the piston downwards and outwards,
3 crank-shaft by means of the connecting-rod and
>th valves remain closed from the beginning to nearly
this stroke. The exhaust valve g is opened by the
before the end of the stroke and part of the burned
ie into the air, so that the pressure in the cylinder
as low as that of the atmosphere. It is during this
stroke of the piston that work is done and a forward
given to the piston, so that it is called the workinsr
tptdse stroke, explosion stroke, or combustion stroke,

view (d) the piston d is seen on the fourth and last
the cycle. During this stroke it moves upwards,
3n by the crank-shaft, and expels the greater part
aining burned gases from the cylinder through the
)rt. However, the combustion chamber, between
r head and the face of the piston, when at the top of
its stroke, remains filled with the burned gases at the com-
pletion of this stroke. The pressure of these residual gases is
generally about the same as, or somewhat higher than,- that of

Digitized by

Google

§2 GASOLINE AUTOMOBILE ENGINES 13

the external atmosphere. The inlet valve remains closed during
this stroke and the exhaust valve remains open, it being closed
about the time that the piston reaches the end of its stroke.
This upward movement of the piston is known as the exhaust
stroke, and its completion ends the cycle of operations. Fol-
lowing the exhaust stroke, the suction stroke again begins and
the series of operations takes place over and over in exactly the

same order.

19. Four-cycle automobile engines are classified as poppet-
valve engines and non-poppet-valve engines, depending on the
type of valve used for controlling the admission of fuel into
the cylinder and the escape of burned gases therefrom.

Poppet-valve engines are those that make use of the
so-called poppet type of valve such as shown in Figs. 2 and 3;
non-poppet-valve engrlnes are those that employ other types
of valves for inlet and exhaust, such as sliding valves or rotary
valves. Non-poppet-valve engines operate on exactly the same
principle as the poppet-valve engine just described.

TWO-CYCLE PRINCIPLE

OPERATION OP TWO-POBT TWO-CYCLE ENGINE

20. The operation of the two-cycle engine differs from that
of the four-cycle engine in that but two strokes of the piston,
instead of four, are required to complete a cycle; or, in other
words, each downward stroke of the piston is a power stroke.
This cycle of operations is made possible by making use of an
air-tight crank-case by means of which the charge is compressed
slightly before being admitted to the cylinder, or by employing
a pump or air compressor for this purpose, so that a separate
suction stroke is unnecessary. In addition, the burned gases
are expelled at the end of the working stroke, thus eliminating
a separate exhaust stroke.

The principle of operation of the two-cycle engine is illustrated
diagranunatically in Fig. 4, which shows three cross-sectional

Digitized by

Google

Digitized by

Google

§ 2 GASOLINE AUTOMOBILE ENGINES 15

views of what is known as a two-port two-cycle engine, so named
because only two ports enter the bore of the cylinder, distin-
guishing it from the three-port engine, which has three ports
opening directly into the cylinder. However, the principle on
which the two tjrpes operate is exactly the same. Each view
in the illustration shows the cylinder and crank-case cut in
half, exposing to view the various parts of the engine and
showing the different positions of the piston. At a is shown
the piston; at 6, the crank-shaft; at c, the crank; at d, the
crankpin; at e, the connecting-rod; at /, the exhaust port; at g,
the inlet, or transfer, port; at fe, the transfer passage, or by-
X^ass, leading from the crank-case to the cylinder; at t, the inlet
valve in the crank-case; at /, a deflector, or baffle plate, on the
«id of the piston; at i, the spark plug at which the spark is
produced; and at /, the crank-case.

21. In Fig. 4 (a) it may be assumed that the cylinder has
been filled with a combustible mixture and the piston is com-
pressing this charge during its inward stroke. At the same
time, the partial vacuiun created by the upward movement of
the piston draws a fresh charge into the crank-case / through
the inlet valve t. At about the end of this stroke the mixture
of gasoline vapor and air, which has been compressed into the
compression space at the top of the cylinder, is ignited by a
spark formed at the spark plug k. This completes the first
stroke of the cycle, which is called the compression stroke.

22. During the second stroke combustion takes place;
that is, the charge in the cylinder is burned. The piston is
forced downwards by the rapid expansion of the burned gases
and a rotary motion is given to the crank-shaft by means of
the connecting-rod and crank. The outward motion of the
piston on this stroke slightly compresses the mixture in the
crank-case Z, the inlet valve i having been closed at about the
end of the first, or inward, stroke. This downward movement
of the piston, called the impulse stroke, is illustrated in (6).

As the piston approaches the completion of the impulse
stroke, it begins to uncover the exhaust port /. As soon as
the edge of this port is uncovered, the burned gases in the

Digitized by

Google

16 GASOLINE AUTOMOBILE ENGINES § 2

cylinder begin to escape into the atmosphere. This escape is,
or should be, rapid enough to allow the pressure in the cylinder
)w that of the precompressed combustible mixture
ik-case by the time the piston has moved out far
)egin to tmcover the transfer port g, through which a
e then begins to enter the cylinder and to drive out
gases.

shows the burned gases escaping and a fresh charge
1 into the cylinder. The baffle plate ; deflects the
harge, so as to prevent it from flowing out with
gases. The more or less complete expulsion of the
es and the drawing of a fresh combustible charge
linder are accomplished during the time the piston
through a small portion of the latter part of the
:oke and early part of the inward stroke. The ports
)sed by the piston during the early part of the inward
T which the fresh charge is compressed in the com-
imber, and more combustible mixtvu-e is drawn into
ase.

; valve i opening into the crank-case may be operated
matically by the suction of the piston or mechanic-
ms of a cam and push rod.

le series of operations taking place during the two-
e in the form of engine just described may be tabu-
lows:

• TWO-STROKE CYCLE

I Crank-Case

First Stroke, Inwards

ion; pressure rises; Suction; inlet valve open;

*ar end of stroke, pressure falls below atmos-

Dy explosion and phere.
)f pressure.

Second Stroke, Outwards
Expansion; pressure falls; Compression; pressure rises
exhaust followed by entrance to from 4 to 8 pounds; char-
of fresh mixture from crank- ging cylinder; pressure falls
case. to atmospheric pressure.

Digitized by

Google

§2 GASOLINE AUTOMOBILE ENGINES 17

OPERATION OP THBEE-POBT TWO-CYCXE ENGINE

24. The three-port two-cycle type of automobile engine
differs from the two-port two-cycle type in that the inlet port
opens into the cylinder bore at a point near the crank-case
and is opened and dosed by the piston, instead of opening
directly into the crank-case. This arrangement ob\dates the use
of a valve of any kind, as the piston takes the place of valves,
so that the engine is also known as a valveless iwo<ycle engine.

A three-port two-cycle en-
gine is illustrated diagramma-
tically in Fig. 5, which is a
cross-sectional view of a cylin-
der of an engine of this type
and shows the location of the
various ports. The inlet port
is seen at a, the transfer port
at 6, and the exhaust port at c.
In the position shown the pis-
ton d has just completed its
downward, or power, stroke
and a fresh charge is flowing
from the crank-case e through
the transfer passage/and trans-
fer port b into the cylinder.
The pressure of this incoming
fresh charge helps to drive the
products of combustion, or
exhaust gases, out through the
exhaust port c, as indicated
by the curved arrows.

Fig. 5

25. The operation of the engine shown in Fig. 5 is as follows :
Starting with the position shown, as the piston moves on its
upward stroke the combustible mixture is compressed into the
compression space in the upper part of the cylinder, and at
the same time the inlet port a is uncovered by the piston so
that a fresh charge is drawn into the crank-case by the suction

Digitized by

Google

18 GASOLI^ AUTOMOBILE ENGINES §2

of the piston. At ^bout the end of this stroke the mixture in
the upper part of the cylinder is fired by a spark produced at
the spark plug g and the piston is driven downwards on its
second, or impulse, stroke by the force of the resulting explosion.
During this downward movement of the piston the fresh charge
that had been drawn into the crank-case is slightly precom-
pressed so that it will flow into the cylinder through the transfer
passage / when the transfer port b is uncovered. As the piston
nears the end of its impulse stroke the exhaust port and transfer
port are uncovered, admitting the fresh charge into the cylinder
and allowing the exhaust gases to escape into the atmosphere.
At the end of the impulse stroke the conditions indicated in the
illustration again exist and the cycle is completed. This cycle
of operations is gone through again and again.

The raised portion h on the face of the piston acts as a deflec-
tor, or baffle plate, which prevents the fresh charge from escap-
ing with the burned gases through the exhaust port. Other
parts of the engine which are shown are the connecting-rod i
and the crank-pin k.

TYPICAL AUTOMOBILE ENGINES

POUR-CYCLE ENGINES

ARBANOEMENT OF ENGINE CYLINDERS

26. General Eng^ine Construction and Control. — ^The
typical automobile engine has four or six cylinders, is of the
vertical four-cycle type, and runs at an average speed of about
1,500 revolutions per minute when at full speed. Except in
rare cases the maximum speed is about 1,800 revolutions per
minute. Automobile engines develop from 20 to 80 horse-
power, depending on the size and number of cylinders. The
engine is ordinarily governed by regulating the amount and
quality of the charge that enters the cylinders, and by varying
the time at which the mixture is fired. This is accomplished by
the levers that are usually located on or near the steering wheel
in front of the driver, although in some engines the time of

Digitized by

Google

§2

GASOLINE AUTOMOBILE ENGINES

ignition is varied by an automatic device, or governor, so that
no hand spark lever is necessary. Some engines are also pro-
vided with an automatic governor by means of which the fuel
supply is automatically regulated and the speed controlled
within certain limits.

In a number of the earlier makes of automobiles, engines
with a single cylinder or with two cylinders were used as a
means of propulsion, but as the automobile industry developed,
engines with a greater nxunber of cylinders were required in
order to secure the power and smooth running demanded in the
modem pleasure car. As a result, the four- and six-cylinder
four-cycle engines are used on practically all pleasure cars of
today, and the single- and double-cylinder types are not being

Pig. 6

manufactured for this piupose, although a few of these engines
are still ini existence.

27. Two-Cylinder Arrangement. — ^The most popular
type of two-cylinder four-cycle automobile engine manufac-
tured is known as the doyble-opposed engine, which has its
cylinders arranged horizontally as shown in Fig. 6. The two
cylinders c are placed on opposite sides of the crank-shaft a,
and the cranks b are directiy opposite each other. By this
arrangement of cylinders, the explosions and consequent
impulses on the piston occur every revolution, first in one
cylinder and then in the other. While one of the pistons d is on
its impulse stroke, the other is on its suction stroke.

Both pistons move toward the crank-shaft at the same
instant and with the same speed; they also recede from the

Digitized by

Google

lOBILE ENGINES § 2

each having the same speed

They are therefore balanced

ght tendency to move sidewise

are not exactly opposite each

are not exactly in Une.

ylinder four-cycle automobile
he cylinders arranged side by
rank-shaft, as shown in Fig. 7,
eneral use in pleasure cars and
are not now manufactured for
that purpose. Such engines
were usually made with the
cranks a, Fig. 7, side by side so
that the pistons b moved in
unison. This arrangement
secures an equal time interval
of one revolution of the crank-
shaft between the impulses;
when one piston is moving
down on its power stroke the
other is moving down on its
suction stroke, so that the
impulses alternate, occurring
first in one cylinder and then
in the other. However, with
the cranks arranged in this
way it is extremely diiBcult to
balance the moving parts so as
he automobile. When the two
I part, as shown in the illustra-
ers, and are said to be en bloc,
which is a French expression for "in block."

29. Four-Cylinder Arrangement. — ^The four-cylinder
four-cycle gasoline engine, which is the most widely used type
of automobile engine, has its cylinders vertically arranged on
one side* of the crank-shaft. This arrangement is seen in
Fig. 8, which is a diagrammatic illustration showing the cylin-

Digitized by

Google

§2 GASOLINE AUTOMOBILE ENGINES 21

ders cut in half and exposing to view the pistons a, the cranks 6,
and the connecting-rods c.

For each cylinder of a four-cylinder engine there is a corre-
sponding crank; hence, in this engine there are four cranks,
each one being part of the crank-shaft d, which is offset to form
the cranks as shown. In order to secure a uniform application
of power and smooth running of the engine, it is essential that
the cranks be arranged around the crank-shaft in such a man-
ner that no two pistons will be on their impulse strokes at the
same time, but that the explosions in the various cylinders wiU
occur in regular order with equal intervals of time between
them. This result is obtained by placing the cranks so that
the two end ones are on one side of the crank-shaft and directly
opposite the two middle ones, which are on the other side of
the crank-shaft. In other words, the cranks of a four-cylinder
four-cycle engine are arranged so that when the two end ones
stand vertically downwards, the two middle ones stand vertically
upwards, as shown in Fig. 8. The two outer cranks are then
said to be at an angle of 180^ with the two inner ones.

30. Order of Explosions of Four-Cyltnder Engines.

With the cranks of a four-cylinder four-cycle engine arranged
as shown in Fig. 8, two of the pistons will be descending while
two are ascending. For instance, while the pistons in cylin-
ders 1 and 4 are descending on their working and suction strokes,
respectively, those in cylinders £ and S are moving upwards
on their compression and exhaust strokes. Ehiring the half
of a revolution of the crank-shaft represented by these move-
ments of the pistons, the explosion occurs in cylinder 1 and
work is done in that cylinder. At the same time a charge is
being compressed in cylinder £, so that during the following
half revolution, the piston in cylinder ;^ is on its working stroke,
that in cylinder S is on its suction stroke, and those in cylin-
ders 1 and 4 are moving upwards on their exhaust and com-
pression strokes, respectively. Ehiring the third half revolu-
tion, the pistons in cylinders 1 and 4 again descend, this time,
however, with that in cylinder 4 on its working stroke and that
in cylinder i on its suction stroke; the pistons in cylinders 2

222B— 10

Digitized by

Google

22 GASOLINE AUTOMOBILE ENGINES § 2

and S are at the same time ascending on their exhaust and com-
pression strokes, respectively. On the fourth half revolution
of the crank-shaft, when the pistons in cylinders i^ and 3
descend, that in S is on its working stroke, and that in ;^ is on
its suction stroke, while those in cylinders 1 and 4 move upwards
on their compression and exhaust strokes, respectively. On the
following strokes of the pistons an explosion will again occur
in cylinder 1, the cyde of operations in that cylinder having
been completed, and the same order of events as just named
is repeated as the crank-shaft revolves.

Fig. 8

31. In brief, the order in which the explosions, or impulses,
take place in the various cylinders of a fovir-cylinder four-
cycle automobile engine is as follows: Starting with cylin-
der 1, an explosion first occurs in that cylinder, then one occurs
in cylinder j^, then in cylinder 4» and finally in cylinder S.
Two full revolutions of the crank-shaft are necessary in order
to complete the various operations required to produce an
explosion in each cylinder; hence, an impulse is given to the

Digitized by

Google

§ 2 GASOLINE AUTOMOBILE ENGINES 23

crank-shaft each half of a revolution. The order in which the
imptilses occur in the various cylinders is called the order of
explosions or the order of firing. The order of firing just
explained is said to be one, two, four, three, or more briefly,
1-2-^-3.

Since the pistons in cylinders 1 and 4 move together, or in
tinison. and those in cylinders 2 and S also move together, or
in unison, in a four-cylinder fotir-cycle engine, it is evident
that the events taking place in cylinders 1 and 4 may be
reversed, or those taking place in 2 and 3 may be reversed,
in which case the order of firing becomes one, three, foiu-, two,
or 1-3-4-2. The sequence of events may be traced out in
the manner explained in Art. 30 by substituting cylinder 4
for cylinder 1, or cylinder 2 for cylinder 5, and vice versa.

The two orders of firing just named are used exclusively
in four-cylinder four-cycle automobile engines. The order
employed depends on the manner in which the valve cams
are set to open and close the inlet and exhaust valves; naturally,
the sequence in which the ignition spark is made to occur in
the several cylinders must be the same as called for by the
construction of the engine.

It is the usual practice to assign the number 1 to the cylinder
nearest the front end of the car and to number those to the rear
of it in succession 2, 3, etc.

32« Six-Cylinder Arrangement. — On account of their
flexibility and smooth running qualities, automobile engines
having six cylinders are used extensively, especially in the larger
cars. The six-cylinder engines are much the same in form as
the usual type of four-cylinder engines, the cylinders being
arranged vertically in a row above the crank-shaft.

The cranks in a six-cylinder engine are arranged in pairs,
that is, there are three pairs, each pair consisting of two cranks
located on the same side of the crank-shaft and in the same
plane. The two cranks of a pair may be either adjacent to each
other or separated by other cranks placed between them. A
common arrangement is shown in Fig. 9, which is a diagram-
matic illustration showing the relative positions of the cranks

Digitized by

Google

24 GASOLINE AUTOMOBILE ENGINES § 2

and pistons. The cranks a and/ form a pair, b and e form a pair,
and c and d form a pair, the cranks of each pair being in line, as
shown in view (6). As generally stated, the cranks of cylinders 1
and 6 form a pair, those of cylinders 2 and 5 form a pair, and
those of cylinders S and 4 form a pair. The pairs are located
at equal intervals arotmd the crank-shaft^ that is, at an angle
of 120® with each other. The two pistons of each pair move in
unison, that is, when one piston is on its up stroke, the other
is also on its up stroke, and when one is on its down stroke,
the other is also on its down stroke.

33« Order of Explosions of Six-Cylinder En^^ines.

The impulses in the cylinders of a six-cylinder four-cycle auto-
mobile engine occur at intervals of one-third of a revolution;
therefore, there are three impulses per revolution. Consider-
ing the cylinders as being in pairs corresponding to the three
pairs of cranks, the explosions first occur in one cylinder of
each pair and then in the other cylinder of each pair in the
same order. A common firing order is 1-5-3-6-2-4. With this
order, an explosion first occurs in cylinder 1, then in cylinder 5,
then in cylinder 3, after which the explosions occur in the other
members of the pairs in the same order; that is, first in cylin-
der 6, which completes a pair with cylinder 1 ; then in cylin-
der 2, which completes a pair with cylinder 5; and finally in
cylinder 4, which is the mate to cylinder 3.

Other orders of firing possible with the crank arrangement
shown in Fig. 9 are: 1-2-3-6-5-4, 1-2-4-6-5-3, and 1-5-^
6-2-3. When cranks 3 and 4 and cranks 2 and 5 are inter-
changed, the following firing orders may be obtained: 1-3-2-
6-4-5, l-3-5-fr4-2, l-4r-5-6-3-2, and l-4r-2-6-3-5. In aU of
these firing orders, explosions occur first in any three cylinders
belonging to different pairs and then in the other cylinders of
the pairs taken in the same order. The various orders can be
'traced out just as in a four-cylinder engine by starting with the
explosion stroke in cylinder 1 and the suction stroke in cylin-
der 6, compression and exhaust occiuring in the two cylinders
forming the pair that is 120° behind cranks 1 and 6 and following
out the events of the cycle in each cylinder.

Digitized by

Google

■"—'^'"'^^ T

Digitized by

Google

26 GASOLINE AUTOMOBILE ENGINES § 2

In practice, the different firing orders are obtained by using
different arrangements of the cams which open the inlet and
exhaust valves, and employing ignition systems wired so that
the electric spark is sent to the cylinders in the sequence desired.

TYPICAL POUB-CYLINDEB ENGINES

rpes of Engines. — Four-cylinder four-cycle auto-
yines may be said to be divided into three classes,

on the manner in which the cylinders are assem-
lely: those having their cylinders cast separately;
ing their cylinders cast in pairs; and those having
ders cast in one piece, that is, en bloc. Cylinders
rs are the most widely used, although engines employ-
)ck type of casting are rapidly increasing in ntmiber.
cast separately are decreasing in number. Engines
cylinders cast en bloc have the advantage of being

compact, and their various parts are always in

irlinders Cast Separately. — ^An example of a four-
)ur-cycle automobile engine with the cylinders cast
is presented in Figs. 10 and 11, which show two
be Overland model 71 engine. In Fig. 10 is seen a
udinal section and side view, and in Fig. 11 is shown
ition through one of the cylinders. In reading the
I both illustrations should be referred to. Each of
ylinders, a, 6, c, and d, is a separate casting and is
uuivcvj. j>cparately to the crank-case e. Both the inlet and the
exhaust valves are located on the same side of the engine, as
shown at / and g, thereby permitting the use of a single cam-
shaft h for operating both sets of valves. The cam-shaft is
driven from the crank-shaft by means of gears enclosed in the
casing i. At the forward end of the engine and driven from
the crank-shaft by the belt ; is a fan fe, which is a part of
the cooling system, and at the rear end is the flywheel /,
inside of which is a clutch for connecting the engine to the
driving mechanism of the automobile. The toothed wheel m

Digitized by

Google

Digitized by

Google

28 GASOLINE AUTOMOBILE ENGINES §2

accommodates a silent chain that turns a dynamo used for
supplying current for electric lighting. The engine cylinders are
cooled by means of water flowing through the jacket spaces n.

Digitized by

Google

§2 GASOLINE AUTOMOBILE ENGINES 29

atmosphere to provide a way of escape for any hot gases going
past tiie pistons. The breather pipe is also used as a filler
pipe through which lubricating oil can be poured into the crank-
case. The spark plugs r in this engine are located directly
over the inlet valves, and the priming valves, or cups, s are
located directly over the exhaust valves. An oil pump t forces
the lubricating oil from a reservoir u in the bottom of the
crank-case through certain pipes and into the troughs v^ from
which it is picked up by the ends of the connecting-rods w.

The cranks of the engine shown in Figs. 10 and 11 are
arranged in the usual manner, that is, when the two middle
cranks x and y stand vertically downwards, the two end cranks
o' and b' stand vertically upwards. The operation of the engine
is on the ordinary four-cycle principle, the explosions occurring
in the order 1-3-4-2. The engine is supported in the frame of
the automobile at two points near the rear end and at one point
in front. This method of support is known as the three-point
suspension. The advantage claimed for suspending the engine
at three points is that it is not subjected to all of the torsional
stresses set up in the frame by the car turning comers or travel-
ing over rough places. In an engine with cylinders cast sep-
arately there are usually five crank-shaft bearings — one between
each two cylinders, and one at each end, as seen at c\

36. By referring to Fig. 11, it is seen that the center line
A B oi the cylinder does not pass through the center C of the
crank-shaft; or, in other words, when the center of the crank-
pin d' is at its lowest position it does not lie on the center line
AB oi the cylinders. Cylinders arranged in this manner are
said to be offset.

The principal object of oflfsetting the cylinders of an auto-
mobile engine is to obtain a more nearly perpendicular pres-
sure on the crank during the working stroke, and thus reduce
the sidewise thrust of the piston against the cylinder wall and
lessen the consequent wear.

37. Cylinders Cast in Pairs. — ^An external view of a
four-cylinder four-cycle automobile engine having its cylinders
cast in pairs is presented in Fig. 12, which shows the engine

Digitized by

Google

30 GASOLINE AUTOMOBILE ENGINES § 2

used on many Buick automobiles. A feature of this engine is
that the inlet and exhaust valves are located in the cylinder
heads and are operated from a single cam-shaft by means of
rocker-arms and push rods. The cam-shaft is located on the
right side of the engine, when viewed from the driver's seat ir
the car. The carbureter a and the inlet and exhaust mani
folds b and c, respectively, are located on the left side. The
air-circulating fan d is driven from the crank-shaft by the
belt e. Each cylinder block, or casting, /, containing two cylin-
ders, is bolted to the crank-case g, and the whole is supported

Fig. 12

on the frame of the car by the arms ft, two of which are located
on each side of the engine. The crank-case is provided with
two breathers for allowing hot gases to escape.

38. A view of the right side of the Buick engine, part of
which is shown in section, is presented in Fig. 13. On this
side of the engine is located the cam-shaft a, which is driven
from the crank-shaft b by the helical gears c and d. The
shaft Cf which drives the magneto and the water pimip, is rotated
at crank-shaft speed by means of the helical gear /, which
meshes with the gear d on the cam-shaft. The magneto, which

Digitized by

Google

Digitized by

Google

32 GASOLINE AUTOMOBILE ENGINES § 2

is not shown in the illustration, is located near the center of the
engine on the right side. The water pump is seen at g. The
cooling water is circulated from the radiator through the pipe h
to the pump and thence into the cylinder water-jackets i by
way of the pipe /. From the water-jackets, it flows back into
the radiator through the pipe k.

The inlet valves / and exhaust valves m are located in the
cylinder heads. The inlet valves / are arranged side by side
in each pair of cylinders, with an exhaust valve m on each ade
of them. The valves are assembled in cages n, which can be
removed by imscrewing the caps o; the valves are operated
by the rocker-arms p and the push rods q. The push rods
are raised by the cams r on the cam-shaft, and their upward
movement in turn raises one end of each rocker-arm. The
other end of each rocker presses against the top of a valve stem,
hence each upward movement of a push rod forces the corre-
sponding valve open against the pressure of its spring. The
valves in this engine are timed so as to give a firing order of
1-3-4-2.

The crank-shaft 6 is of the three-bearing type; that is, it
turns in a bearing ^ at each end and one in the middle. The
crank-case is divided into two compartments. The lower
oxnpartment t serves as an oil reservoir from which the lubri-
cating oil is circulated throughout the oiling system by means
of a gear-pump w, which is driven from the crank-shaft by means
of bevel gears and a vertical shaft. The upper compartment v
is the crank-case proper and contains oil troughs w into which
the scoops X, on the lower ends of the connecting-rods, dip
and gather up oil for lubricating the cylinders and connecting-
rod bearings. In the broad flywheel ;v is a cone clutch that
connects or disconnects the engine from the driving mechanism
of the car when desired. The clutch consists of the cone 2,
which is normally held against the inner conical surface of the
fljrwheel by the spring a' and is faced with the leather b\ The
cone z is coupled to the driving mechanism of the car, and
the clutch is disengaged by compressing the spring a' by means
of a foot-pedal, thus separating the outer surface of the cone
from the inner surface of the flywheel.

Digitized by

Google

§2 GASOLINE AUTOMOBILE ENGINES 33

The spark plugs in this engine are located along the side of
the cylinders, as seen at c', A pointer d\ fixed to the rear
cylinder, indicates by means of marks on the flywheel rim the
time at which the valves should be opened and closed, and the
positions of the dead center of the cranks.

39. Cylinders Cast En Bloc. — ^Fig. 14 is a view of the
inlet side of the Chalmers "Thirty-six" motor, which is an
example of a four-cylinder four-cycle engine having its cylinders
cast en bloc. A front-end view of the same engine is shown in

Digitized by

Google

34 GASOLINE AUTOMOBILE ENGINES § 2

Fig. 15. The carbureter a is located on the right side of the
engine and the magneto b and water pump c on the left side.
In the end view, Fig. 15, is seen the arrangement of. the gears
by means of which the cam-shaft and magneto shaft are driven.
The diameter of the gear d on the cam-shaft is twice that of the
gear e on the crank-shaft, and the diameter of the gear/ on the
magneto shaft is the same as that of the gear e. This arrange-
ment gives the gear ratios required to drive the cam-shaft at
one-half crank-shaft speed, and the magneto shaft at crank-
shaft speed. The gear g is an
idler gear and is used simply to
connect the gears d and e. It has
no effect on the gear ratio but
causes the cam-shaft to be rotated
in the same direction as the crank-
shaft. In some engines the crank-
shaft gear meshes directly with
the cam-shaft gear, and the two
shafts rotate in opposite direc-
tions. The cam-shaft may rotate
in either direction, provided the
cams are designed so that they will
work properly in that direction.
In this engine, the inlet valves
^°- '^ are located in the cylinder heads

imder the caps fe, and are operated from the cam-shaft by
means of the push rods i and the rocker-arms /; the exhaust
valves are located on one side and are operated directly by the
push rods k. The inlet manifold /, leading from the carbureter a
to the intake passages, is on the right side of the engine, and
the exhaust manifold w is on the left side. The carbureter
employed on this engine is warmed by hot water from the
cylinder jacket; the water flows through a jacket space around
the carbureter, entering it by the pipe n and leaving by the
pipe Of which leads into the cooling system near the pump. A
breather pipe, which is also used as an oil funnel, is seen at p.
The foot-pedal q operates the clutch, which is contained in the
case r, and the levers s are part of the connections running from

Digitized by

Google

Pig. 16

Digitized by VjOOQ IC

86 GASOLINE AUTOMOBILE ENGINES § 2

the hand spark lever on the steering column to the spark-
timing device on the magneto.

40. A part longitudinal section of the Chalmers four-
cylinder engine is presented in Fig. 18. The view shows at a
the inside of the first cylinder and the location of the inlet
valve by which opens downwards into the center of the combus-
tion chamber. In the second cylinder, part of the exhaust
valve chamber is cut away, exposing to view the exhaust valve c,
which opens upwards into the side, x)r projecting part, of the
combustion chamber. The spark plugs d are placed directly
over the exhaust valves. The crank-shaft ^ is of the two-bearing
type and is supported at its ends by the ball bearings /. A
single cam-shaft g operates both inlet and exhaust valves,
two of the gears by which it is driven from the crank-shaft
being shown at h and i. The bottom of the crank-case contains
four troughs ; into which' lubricating oil is pumped from the
oil reservoir k. The ends / of the connecting-rods dip into
these troughs and splash the oil over the interior of the engine,
thus lubricating the moving parts. The fan pulley is seen at tn
and the flywheel at n.

TYPICAL SIX-CYLIKDEB ENGINES

41. Cylinders Cast Separately. — Six-cylinder four-cycle
automobile engines usually have their cylinders cast in blocks
of two or more, although in a few the cylinders are cast sepa-
rately. An example of the latter method of construction is the
Franklin six-cylinder air-cooled engine shown partly in side
view and partly in section in Fig. 17. The distinguishing feature
of this engine is that its cylinders are cooled by means of air-
currents flowing over them instead of by means of the tisual
water-jacket. The cylinders a are provided with flanges 6
that increase their radiating surface and make it possible for
the cool air flowing around them to carry off enough heat to
sufficiently cool the cylinders.

Both the inlet valves and the exhaust valves are located in
the cylinder heads, as shown in the first cylinder, in which c
is the inlet valve and d the exhaust valve. The valves are

Digitized by

Google

222B— 11

Digitized by

Google

38 GASOLINE AUTOMOBILE ENGINES § 2

operated from a single cam-shaft e by means of push rods /
and rockers g. The cam-shaft is driven from the crank-shaft h
by means of the helical gears i and /. A third helical gear k
drives the magneto shaft / from the cam-shaft gear /. An oil
pump m is located on the same side of the engine and receives
its power from the cam-shaft through a vertical shaft n that is
driven by helical gears, one of which is seen at o. By means
of this pimip, the lubricating oil is piunped from the reservoir p
through the lubricating system to the various bearing surfaces.
A multiple disk clutch g, enclosed in the flywheel r, connects
the engine crank-shaft with the driving mechanism of the car.
The inlet manifold is seen at s and the exhaust manifold at t.
The crank-shaft h is supported by seven bearings, one at each
end of the engine and one between each two adjacent cylinders.

42. Cylinders Cast In Pairs and in Threes. — ^The
most common method of grouping the cylinders of a six-cylinder
four-cycle automobile engine is in blocks of two, as shown in
Fig. 1. The advantage of this construction over that in which
the cylinders are cast separately is that a shorter and more
compact engine is obtained and a smaller number of crank-
shaft bearings are necessary. On the other hand, as the number
of cylinders in one block increases, the difficulty of making the
casting also increases. Cylinders cast in blocks of two, or in
pairs, are comparatively easy to make; hence, engines of this
type have certain advantages, from the manufacturers' stand-
point, over engines with all of the cylinders cast in one piece.
However, the compactness and neat appearance of the six-
cylinder engine with the cylinders cast en bloc, are advantages
that are bringing this type of motor rapidly into use.

43. A number of six-cylinder engines are built with the
cylinders grouped in two blocks having three cylinders in each
block, as shown in Figs. 18 and 19. Fig. 18 is a right-hand side
view of the Lozier "Light Six," and Fig. 19 is a left-hand side
view of the same engine. The engine has a bore of 3f inches
and a stroke of 5| inches and is rated at 36 horsepower. Thie
two blocks are seen at a and 6, Fig. 18. The inlet and exhaust
valves are located on this side ot the engine, the valve stems

Digitized by

Google

Digitized by

Google

40 GASOLINE AUTOMOBILE ENGINES § 2

and springs being enclosed. The valves are operated from a
single cam-shaft that is driven from the crank-shaft by means
of gears contained in the casing c. The fuel enters the cylinders
from the carbureter d by way of the intake manifold e, and the
exhaust gases escape through the exhaust manifold /. At g is
a sleeve that surrounds the exhaust pipe and is connected to
the carbureter for the purpose of supplying warm air to aid in
evaporating the gasoline. The djniamo h supplies electricity
for the electric lights on the car, and the electric starting
device i automatically cranks the engine when starting. The
spark plugs ; are located over the inlet valves. The clutch and
transmission gears are located in the casing k, which is rigidly
bolted to the engine crank-case /, thus forming a imit power
plant. The clutch is operated by the foot-pedal m and the
transmission gears by the hand-lever w. The foot-pedal o and
the hand-lever p are for operating the service and emergency
brakes, respectively. The foot-pedal q is the accelerator pedal,
which is used for opening the throttle valve in the carbureter
by foot pressure.

44. The water piunp r and the magneto s are located on the
left-hand side of the engine, as shown in Fig. 19. Both are
driven by the shaft t, which in turn is driven from the crank-
shaft through the gears contained in the casing c. The water
circulation is from the ptmip r through the pipe u to each
casting, thence to the radiator by way of the connection »,
and back to the pimip through a pipe not shown. The breather
pipe w allows the escape of hot gases from the crank-case and
affords a means of pouring oil into the oil reservoir in the
bottom of the crank-case. An oil-level gauge is located at x.
The power plant is supported in the frame of the car by the four
arms y and z, two on each side.

45. Cylinders Cast En Bloc. — ^Fig. 20 shows the outside
appearance of the Studebaker six-cylinder engine. All the
cylinders are cast in one piece a and the valve stems and springs
are completely enclosed, giving the engine a very compact and
clean-cut appearance. All of the valves are located on the left
side of the motor, which is the side shown, and the inlet valves

Digitized by

Google

Digitized by

Google

42 GASOLINE AUTOMOBILE ENGINES § 2

are adjacent to each other. The spark plugs b are located over
the inlet valves, and the priming cups c over the exhaust valves.
The carbureter is on the right side of the engine and the exhaust
pipe d is on the left: A feature of this engine is the location of
the water pump e, which is placed at the forward end of the
cylinders and pumps water into the cylinder jackets in line with
the valves. The pump receives its power from a cross-shaft
that is driven by a worm-gear from the engine crank-shaft.
The magneto is also driven by this cross-shaft, and is located
on the opposite side of the engine. The cooling water is returned
to the radiator through the pipe /. The crank-case g is made

Pig. 20

bottomless and a pressed-steel oil reservoir h containing lubri-
cating oil is bolted to it. The amount of oil in the reservoir
may be ascertained at any time by means of the gauge i. Oil is
poured into the crank-case through the breather pipe ;'. The
engine is supported in the frame of the car by means of four
supports, two of which are located on each side, as shown
at k and I.

UNIT POWER PLANT

46. In general, there are two methods of placing the engine,
clutch, and transmission gears in relation to each other in an
automobile chassis. First, the transmission gears, and in some
instances, also the clutch, may be entirely separate from the

Digitized by

Google

§2 GASOLINE AUTOMOBILE ENGINES 43

engine and be either contained in a separate casing or form part
of the rear axle; and second, the three units may be enclosed
in a single rigid casing, forming the unit i>ower plant type of
construction. In the first method, the change-speed gears are
connected to the engine by a shaft fitted with either one or two
universal joints to give flexibility and thus relieve the parts
of the strej>ses that otherwise would be thrown on them in
passing over rough, imeven roads. In the tmit power plant, the
parts are held rigidly in alinement by means of the casing.

47. An example of a unit power plant is presented in Fig. 21,
in which {a) is a side view and part longitudinal section and
(jb) is a top view of the Model 31 imit power plant manufactured
by the Northway Manufacturing Company. The transmission
housing a is bolted to the engine casing 6 so as to form a single
rigid casing in which the engine, clutch, and transmission are
enclosed.

The engine is of the six-cylinder type, with its cylinders cast
in pairs, and all the valves c and d are located on the left side
and operated from a single cam-shaft e, A feature of this
engine is that the cam-shaft e and pump shaft/ are driven from
the crank-shaft by means of a silent chain, represented by the
dotted lines g. This aids in making the engine run quietly.
The clutch is located inside of the flywheel h and is of the cone
type.

The chief advantages claimed for the imit power plant are
that the imit casing keeps the oil in and the dust out and that
every part is held in absolute and imdisturbed alinement imder
all conditions. Another advantage is that it petmits the power
plant to be assembled as a whole and put into position without
fitting it into place. A disadvantage is that with the unit
construction, it is sometimes diflScult to remove one part with-
out first removing many other parts.

ENGINE SUSPENSION

48. An automobile engine may be suspended from the frame
of the car by either one of two methods, namely, by tliree-polnt
suspension, or by four-i>olnt suspension. With the three-

Digitized by

Google

44 GASOLINE AUTOMOBILE ENGINES § 2

point method of support, the power plant is carried by two
rigid supports at one end and by a single pivotal support at
the other. In some cars the power plant is suspended in front
from the main frame or the subframe by two arms, and in the
rear from a cross-member of the frame by a single pivotal
joint; in other cars the two supports are at the rear and the
single support in front. For example, the unit power plant
illustrated in Fig. 21 is suspended in this manner. The rear
of the power plant is carried by two arms i and /, view (6),
which rest on longitudinal members of the frame, and the
forward end is carried by the support fe. The front sup-
port fe is in the form of a bearing that is bolted to the cross-
member of the frame and carries the forward end of the engine
through the part /, which extends into k. The part / is free to
turn in the support ky and hence any twisting motion that is
given to the power plant through the arms i and ; does not tend
to distort the engine and throw it out of alinement, but merely
turns the entire power plant in the bearing k.

In the four-point suspension, the engine or power plant is
supported by the frame of the car at four points. Four arms
or supports extend from the power plant casing or from the
crank-case to the side members of the frame to which they are
rigidly attached. The engine and transmission may each be
supported or carried separately in their own casings, or they may
be combined into a unit power plant and the whole carried at
four points. A good example of four-point suspension is the
engine shown in Fig. 12, which is carried on the side members
of the frame by two arms h on each side of the crank-case.

49. Each method of supporting the power plant of an
automobile has certain advantages peculiar to itself. The
advantage claimed for the three-point suspension is that it
prevents twisting stresses from being transferred from the frame
of the car to the engine, thus throwing the moving parts out of
alinement. On the other hand, it is claimed by the adherents
of the four-point method of suspension that, although the
three-point suspension is theoretically correct, from a practical
standpoint the four-point suspension is the more satisfactory.

Digitized by

Google

Digitized by

Google

a22B 12

Digitized by

Google

Digitized by

Google

Digitized by

Google

§ 2 GASOLINE AUTOMOBILE ENGINES 45

The engine with four points of suspension is more stable and less
inclined to rock under heavy loads tinder varying conditions.
It is also claimed that with the four-point suspension, the
engine is held rigid by means of its supports and the frame gives
the desired flexibility. As a matter of fact, both methods of
power plant suspension
are used with success on
all kinds of automobiles.

60. The two meth-
ods of suspension can
be compared by observ-
ing the two views of
Fig. 22. In (a) the
engine a and the trans-
mission b are located in
separate casings, each
casing being suspended
from the frame by f our
arms. In (6) the
engine a and trans-
mission b are enclosed
in a single casing and
the whole is suspended
from the frame by the
two arms c in the front
and the joint d in the
rear. The pivotal joint
d rests on a cross-
member e of the frame.

It must not be
iniagined that a three- ^'^' ^

point suspension can be applied only to a unit power plant;
the engine alone is often suspended from the frame on three
points and the transmission carried as a separate tmit. In
other words, the term three-point suspension refers to the
number of points at which the engine or power plant is sup-
ported, regardless of the m^iner in which the engine is encased.

Digitized by

Google

46 GASOLINE AUTOMOBILE ENGINES §2

TWO-CYCIiB ENGINES

ABRANGEMENT OF TWO-CTCLE ENGINE CTLINDEB8

51, A two-cylinder two-cycle engine ustially has its cylin-
ders arranged side by side, as in Fig. 23, and the cranks at an
angle of 180® apart, or directly opposite each other. In other
words, while one piston is moving downwards on its imptilse
stroke the other is moving upwards on its compression stroke,
so that the explosions alternate, occurring first in one cylinder
i M and then in the other. By

this arrangement an impulse
occurs every half revolution,
and the moving parts are
well balanced.

52. Three-cylinder two-
cycle engines are generally
arranged as shown in Fig. 24.
The cranks are 120° apart,
that is, they are arranged at
equal distances aroimd the
crank-shaft, so that the
impulses occur every third of
a revolution. With this
arrangement and starting
with the first cylinder, an
explosion occurs first in
cylinder 1 , then in cylinder 5,
^'°- ^ and lastly in cylinder 2, or, in

other words, the order of firing in such an engine is 1-3-2.

53. In four-cylinder two-cycle engines all the cylinders
are generally in Une on one side of the crank-shaft, as seen in
Fig. 26. The cranks are arranged 90° apart, hence in such an
engine four impulses occur at equal time intervals for each
revolution of the crank-shaft. In order to balance each other
and thus prevent any great vibration, the cranks are arranged

Digitized by

Google

Fig. 24

Fig. 26
47

Digitized by VjOOQ IC

48 GASOLINE AUTOMOBILE ENGINES §2

so that cranks 1 and 2 are directly opposite each other and
cranks S and 4 are directly opposite each other, as seen in the
illustration. Beginning with cylinder 1, an explosion occurs
first in that cylinder, then in cylinder ^, then in cylinder 2^
and finally in cylinder 5; or, in other words, the firing order is
l-4r-2-3. The arrows in the illustration show the direction in
which the different pistons are moving, and the numbers at
the top indicate the usual numbering of the cylinders, No. 1
being at the front end of the engine and No. 4 at the rear.

EXAMPLES OF TWO-CTCLE AUTOMOBILE ENGINES

54. Application of Two-Cycle Principle. — ^The use of
the two-cycle automobile engine is practically confined to the
high-wheel type of motor vehicle known as the motor buggy ,
so named from its resemblance to the ordinary horse-drawn
buggy, and to a few makes of motor trucks, or commercial
vehicles.

The two-cycle engine is not used to any extent in automobile
practice, principally because it is not as economical as the
four-cycle engine in the use of fuel and oil, and because its
construction is not such as to readily adapt it to high speeds.
In this type of engine the cylinder is not completely cleared of
exhaust gases at the end of the working stroke, so that the
burned gases are liable to mix with the fresh charge and make
a poor combustible mixture. This is. most likely to occur
when miming at the high speeds required in pleasure cars.
Various types of two-cycle engines have been designed from
time to time for use on pleasure cars, and although these have
their good feattures, practically all have had to give way to the
more popular four-cycle engine.

55. Two-Cylinder Two-Cycle Engine. — ^An external
view of a two-cylinder two-cycle engine of the two-port type,
used on the Duryea motor buggy, is shown in Fig. 26. The
cylinders a and b are placed side by side on the same side of the
crank-shaft c, and the flywheel d is placed between them. The
inlet ports leading into the crank-cases are located at e and

Digitized by

Google

§2 GASOLINE AUTOMOBILE ENGINES 49

the exhaust ports at / on the opposite side of the cylinders.
Spark phigs g are screwed into the cylinder heads for the pur-
pose of igniting the charge at the proper time.

This engine is provided with means for turning the flywheel
over from the seat when starting. The arm A, which is free to
rotate about the crank-shaft, is provided with a pawl i that can
be made to engage in notches / placed at intervals around the
flywheel rim. A wire and rope connection extends from the
arm and pawl to a handle at the driver*s seat. The engine can
be turned over by
pulling on this connec-
tion, thus engaging
the pawl in one of the
notches and rotating
the flywheel.

56. A cross-sec-
tional view of one of
the cylinders of the
engine illustrated in
Fig. 26 is seen in
Fig. 27, which shows
the piston at the bot-
tom of its stroke with
the transfer port a
and the exhaust port b
open. The charge

enters the crank-case Pig. 26

through the crank-case inlet port c. This port is controlled by
a check-valve d, which prevents the combustible mixture from
flowing back into the inlet pipe or the carbureter when the pis-
ton is on its downward stroke. Normally the valve is held to
its seat by a light spring, but when a vacuimi is formed in the
crank-case by the upward stroke of the piston, the valve opens
inwards and allows the mixture to enter the crank-case. The
deflector on the piston face is shown at e, and the spark plug at/.

67. The arrangement of the cranks of the engine illustrated
in Fig. 26 is shown in Fig. 28. This illustration shows the

Digitized by

Google

60 GASOLINE AUTOMOBILE ENGINES § 2

pistons a and b connected to
the cranks c and d by the con-
necting-rods e and /, respect-
ively. The cranks are located
on opposite sides of the
crank-shaft so that the explo-
sions in the cylinders will
alternate, as is the usual cus-
tom in two-cylinder two-cycle
engines. Each crank is pro-
vided with a counterweight g
that serves to balance the
moving parts of the engine.
The crank-shaft h rotates in
the roller bearings i, which
are supported by the frame
of the car. The rollers /
drive the road wheels of the
motor buggy.

58. Detailed views of

one of the cylinders removed

from the engine illustrated in

^'*'- ^^ Fig. 26 are shown in Fig. 29.

In view (a) is seen the inlet side of the cylinder with the inlet

port at a, and in view (6) is seen the exhaust side with the

Pig. 28

exhaust port at b. Copper spines for the purpose of carry-
ing off the excess heat and thus preventing damage from

Digitized by

Google

§ 2 GASOLINE AUTOMOBILE ENGINES 51

over-heating are bound to the outside of the cylinders, as seen in
view (6) These spines, or projections, serve the same ptirpose

W Pig. 29 fb)

as the cooling water in the engines previously described.

69. Three-Cylinder Two-Cycle Engine. — ^The Chase

three-cylinder two-cycle en r^ -McIj is of the three-port
type, is illustrated in Figs. 30 ai < Fig. 30 shows the engine

Digitized by

Google

52 GASOLINE AUTOMOBILE ENGINES § 2

mounted on the frame of the car with part of the hood a and
mud pan 6 cut away, exposing to view the intake side of the
motor. The carbureter is located at c and is connected to the
cylinders d by the intake manifold e^ through which the charge
is drawn into the crank-case /. At g is the exhaust manifold,
by means of which the exhaust gases escape into the exhaust
pipe and thence to the atmosphere. The crank-shaft h extends

lengthwise through the crank-
case and is provided with the
starting crank / for the purpose
of turning over, or cranking, the
engine when starting. This
engine is of the air-cooled type,
that is, the cylinders are cooled
by currents of air flowing around
and over them. Flanges are
cast integral with the cylinder
walls to increase their radiating
surface and better to enable the
air to carry away the heat.

60. Fig. 31 shows a cross-
sectional view of one of the cyl-
inders of the engine illustrated
in Fig. 30. As far as possible
the same parts in the two illus-
trations are lettered the same.
The piston fe, Fig. 31, is seen at
the bottom of its stroke with
^*^'^^ the crank-case inlet port I

closed and the transfer port m and the exhaust port n open.
The operation of this engine is identical with that of the three-
port engine shown in Fig. 5. A charge flows into the crank-
case / on the upward stroke of the piston when the inlet port /
is opened, and is slightly compressed on the downward stroke,
at the end of which the transfer port m is uncovered and the
mixture rushes into the combustion chamber through the pas-
sage o. On the next upward stroke of the piston the charge

Digitized by

Google

§ 2 GASOLINE AUTOMOBILE ENGINES 53

is compressed in the cylinder, after which it is ignited and the
resulting expansion drives the piston downwards again, a new
charge being precompressed in the crank-case at the same
time. The exhaust gases escape through the port n at the end
of each down stroke. A feature of this engine is the use of a
baf&e plate p in the combustion chamber. One of these plates
is located on the exhaust side of each cylinder, and is for the
purpose of preventing the fresh charge in the combustion
chamber from escaping by way of exhaust port n at the begin-
ning of the compression stroke.

232B— 12

Digitized by

Google

Digitized by VjOOQ IC

GASOLINE AUTOMOBILE ENGINES

(PART 2)

DETAILS OF CONSTRUCTION

AUTOMOBIIiE-EINGINE CYUNBERS

WATER-JACKETED CYLIXDEBS

!• Cylinders with Integral Heads and Jackets. — ^The
almost universal practice in water-jacketed automobile-engine
construction is to cast the cylinder body, the head, and the
water-jacket in one piece. In the earlier types of engines it
was common practice to make the cylinder head a separate
casting and bolt it on to the cylinder proper, but at the present
time only a very few ntiakers of automobile engines adhere to
this custom. The chief object of casting the cylinder, the head,
and the jacket in one piece is to avoid packed joints between
the cylinder and the head and between the cylinder and the
water-jacket.

2* The form of an automobile-engine cylinder depends on
the location and arrangemait of the inlet and exhaust valves.
Classified according to the valve location, there are three general
types of cylinders, namely, the l-head, the L-head, and the valve-
in^he-head.

3. In engines of the T-liead type, the inlet and exhaust
valves are located on opposite sides of the cylinder, giving it,
roughly, the appearance of the letter T. This type of cylinder

oorrmaHTBD by intirnationai. tbxtbook company, all iiiaHTs rbmrvbd

Digitized by

Google

GASOLINE AUTOMOBILE ENGINES

§3

is illiistrated in Fig. 1, which shows a cross-sectional view of
one of the cylinders of the National, 4J''X6", four-cycle engine.
The combustion chamber ti and the inlet and exhaust passages 6
are surrounded by the water passages c. This inlet and exhaust
chambers are made alike, and the valves are interchangeable.
The intake pipe is connected to the opening shown at d and the
exhaust pipe to that shown at e, chambers being cored from these

Pig. 1

openings to the valves, as indicated by the dotted lines. The
opening on top of the cylinder at / permits placing the inlet
valve in position or withdrawing it, and also gives access to it;
a corresponding opening g on the opposite side is provided for
the same purposes for the exhaust valve. The openings are
ordinarily closed by means of plugs screwed into them. The
National engine is provided with two separate sets of spark
plugs, and one of these is screwed into the center of each of the

Digitized by

Google

§3

GASOLINE AUTOMOBILE ENGINES

plugs, or caps, that dose the openings/ and g. The opening h
is for a priming cup, and the openings i are provided to accom-
modate the valve-stem guides.

4. When the inlet and exhaust valves are placed together
on the same side of the cylinder and are operated by the same
cam-shaft, the cylinders are said to be of the L-head type.
This tjrpe of cylinder is illustrated in Fig. 2, which shows two
views of one of the cylinders used in the Rambler four-cylinder,
four-cycle engine. View (a) is a cross-section of the cylinder,
and view (fe), a side view and section through the valve cham-

<^)

Fig. 2

bers. A water-jacket a surrounds the upper part of the cylin-
der b and the valve chambers c and d. Valve-stem guides e are
cast integral with the valve chambers, and the valves are made
interchangeable. The valves may be removed by unscrewing
the plugs, or caps, / and g. The spark plug is located over the
inlet valve in the center of the cap /. The cooling water escapes
from the water-jacket through the opening h. The opening i,
which, ordinarily, is closed by a plug, gives access to the inside
of the cylinder. In engines of this type, it is common practice
to place the inlet valves of adjacent cylinders next to each other.

Digitized by

Google

GASOLINE AUTOMOBILE ENGINES

§3

5. Yalve-in-tlie-liead eiiglnes» with cylinder, head, and
water-jacket cast in one piece, usually embody some type of
valve cage containing the valve seat and valve-stem guides. The
valve-in-the-head construction is illustrated in Fig. 3, which
shows a longitudinal section of a pair of cylinders of the Buick
engine. Each cage consists of a cylindrical shell a that fits in a

Pig. 3

bored-out pocket in the cyUnder head and has a large opening
cut through the shell to register with the inlet or the exhaust
passage The cage is forced against a shoulder 6 at the lower
end of the pocket by means of an annular nut c screwed into the
outer threaded end of the pocket. The valve-stem guide d is
supported within the cage by means of a spider e, and the valve
is held to its seat by a spring /, whieh is held in compression

Digitized by

Google

§3 GASOLINE AUTOMOBILE ENGINES 6

between the spring seats g and h. The seat g is prevented from
being forced oflE the valve stem by the cotter i. The valves
are opened by pressure exerted on the upper aids of the valve
stems. The two inlet valves ; and k are located next to each
other at the center of the twin casting, and the two exhaust
valves are located at the ends of the casting, one being shown
at /. This arrangement has the advantage that a single con-
nection from the intake manifold is sufficient for both cylinders.
A single continuous water-jacket m surrounds the entire casting,
and the spark plugs are located on one side, immediately below
the valve cages.

6. The cylinders shown in Fig. 3 have the valves arranged
vertically in the cylinder heads. Another type of valve-in-
the-head engine, in which the valves

are incUned, is illustrated in Fig. 4,
which shows a cross-sectional view
of one of the cylinders (rf the engine
used in the Stoddard-Dayton, model
58, car. In this engine, the valves
are located on opposite sides of the
cylinder and they are operated from
separate cam-shafts by means of
push rods and rocker-arms. The
charge enters the inlet valve cage a
through an opening at b, and the
exhaust gases escape from the
exhaust-valve cage c through an
opening d. The valve cages a and b
are indined at an angle to the ver-
tical and have between them a
jacket space e. A water-jacket / ^'^"^

surrounds the outside of the valve chambers, the combustion
chamber g, and the upper part of the cylinder proper.

7. The chief advantage of having the valves located in
the cylinder head is that a more nearly ideal combustion cham-
ber may be had with this design than with any other. The
ideal combustion chamber is spherical in form, for the reason

Digitized by

Google

6 GASOLINE AUTOMOBILE ENGINES § 3

that a sphere has the least surface area for its cubical contents;
hence, in such a combustion chamber, the loss of heat through
the walls is least. Among the valve-in-the-head cylinders,
those having the valves set at an angk more nearly approach
this form of combustion chamber. However, motors with
the valves located in the cylinder head have the disadvantage
of reqtdring the use of a complicated and more or less noisy
valve-actuating mechamsm. This is a very important con-
sideration, especially in high-speed engines.

T-head and L-head engines have the advantage of simple
valve-operating mechanism. The valves are more easily
removed than in the valve-in-the-head type, and the spark
plugs can be located in the inlet valve chamber, where a fresh
charge is always found* On accoimt of this advantageous
location of the spark plugs, T-head and L-head motors can be
run at a lower speed under no load than can an engine with
the valves in the head. Because of these practical considera-
tions, most manufacturers make use of either the T-head or the
L-head motor for ordinary pleasure car service; valve-in-the-
head engines are used extensively in racing cars.

8. A t3rpe of engine cylinder in which the inlet valve is
located in the head and the exhaust valve at one side is some-
times used. The appearance of the engine is similar to that of
the regular L-head motor, except for the valve-actuating
mechanism. The inlet valve is operated by means of a push-
rod and a rocker-arm, and the exhaust valve, by means of a
valve tappet that operates directly on the valve stem. In
some Chalmers engines, which use this type of cylinder, both
valves are operated from a single cam-shaft. The spark plug
is located over the exhaust valve. This form of cylinder pro-
vides a better shaped combustion chamber than is provided
by the T-head cylinder, and at the same time it allows large
inlet and exhaust passages, as these may be placed on opposite
sides of the engine. This is an advantage over the regular
L-head cylinder, in which the valve passages are more restricted
on account of all the valves being on the same side. On
the other hand, this construction has the disadvantage of a

Digitized by

Google

§ 3 GASOLINE AUTOMOBILE ENGINES 7

somewhat complicated valve-operating mechanism. Also, the
spark plug is located in the exhaust-valve chamber, where a
small quantity of burned gases is liable to become mixed with the
fresh charge and thus make the mixture more difficult to ignite.

9. Cylinders With Separate Heads. — In the early auto-
mobile engines having cylinder heads cast separately, the upper
end of the cylinder

and the water-jack-
eted head were pro-
vided with passages
for the circulation of
the cooling water.
The openings in the
head and the upper
end of the cylinders
were made to match,
and the joints were
made tight by means
of gaskets that con-
tained holes corre-
sponding to the
water passages. The
difficulty of keeping
these narrow gaskets
in place and of pre-
venting the joint
from leaking has led
to the abandonment
of this practice in
engine design, except
in a few special cases.

10. In the Knox ^'^'^

engine, as shown in Fig. 6, the cored openings for commimica-
tion between the water-jacket and the head are omitted and
an outside connection is used instead.

The detachable head a is held in place by four long stud
bdts b that pass through lugs cast on the cylinder head, as

Digitized by

Google

8 GASOLINE AUTOMOBILE ENGINES § 3

shown. Communication between the head a and the water-
jacket c of the cylinder is afforded by a separate detachable
U-shaped hollow fitting d held in place by the yoke e^ which
also serves to hold in place the return-water manifold or pipe
connection ; leading to the radiator. One end of the fitting d
fits in the opening / leading to the cylinder water-jacket, and
the other end fits in the hole g of the cylinder head. A hori-
zontal division plate, which is cast in the head, divides the water
space thereof into two parts. The circulating water from the
cylinder jacket enters the lower space through the opening g
and passes out into the return-water manifold through the open-
ing h. Water from the supply manifold enters the jacket at i.
On the bottom of the head there is a. machined concentric
tongue that fits into a corresponding machined groove in the
upper end of the cylinder casting, and in the groove is placed
a copper-asbestos gasket k that serves to make a tight joint
when the nuts on the stud bolts 6 are screwed down. The
manufacturers daim that, among other advantages of this
construction, the machining of the whole bottom of the head
contributes to the smooth running of multicylinder engines,
because it insures combustion spaces of uniform capacity and
lessens the liabihty to backfiring by eliminating the carbon-
collecting projections, sharp points, rough edges, or uneven
surfaces common to tmmachined castings. Being located in
the head, as shown, the inlet and exhaust valves that control
the flow of the fresh charge and exhaust gases through pas-
sages cored in the head are surrounded by the circulating water
and are thus kept cool.

11. Another example of a detachable water-jacketed cylin-
der head is illustrated in Fig. 6, which shows several views of
the cylinders of the Ford, model T, engine. A side and part
sectional view of the cylinders is shown in (a); a top view,
in (6) ; and a bottom view of the head and a top view of the
cylinders with the head removed, in (c) and (d), respectively.
Each cylinder is of the L-head type, and the four cylinders are
cast en bloc. The cylinder head a is a single casting that is
bolted to the cylinders by fifteen capscrews b. When the head

Digitized by

Google

§3

GASOLINE AUTOMOBILE ENGINES

^_^

fa)

is removed by tmscrewing these capscrews, the tops of the
valves c and the tops
of the pistons d, are
exposed, thus facili-
tating the processes
of removing deposits
of carbon, regrinding
the valves, and re-
moving the pistons
and comiecting-rods.
As shown by the sec-
tional view, the valve
stans are kept cool
by the water circula-
ting in the jacket e
from which the
water passes into the
head through two
passages /, one at
each end of the cyl-
inder casting, corre-
sponding passages g
being formed in the
head, as shown by
the bottom view of
this part. The water
that enters the
water-jacket through
the pipe h passes out
to the radiator
through the pipe
attached to the top
of the head, as
shown. The spark
plugs / are screwed
into the openings k,
so as to project into the combustion chambers / formed in
the head. A copper-and-asbestos gasket is used between the

•^ y^ O O O N. ^

' t0o:aQy

(d)

Pig. 0

Digitized by

Google

10 GASOLINE AUTOMOBILE ENGINES § 3

cylinders and the head in order to form a tight joint. The
gasket is comparatively wide and is not liable to be blown out
on account of the cylinders being cast en bloc.

A special advantage of separate cylinder heads is that they
allow a boring tool to be used to the best advantage and thus
facilitate the boring of the cylinders in their manufacture.
However, their use in automobile engine construction is almost
entirely confined to the Knox and Ford engines.

12. Cylinders With Separate Water- Jackets. — ^The
water-jacket that surroimds the cylinder of an automobile
engine is necessary in order to prevent the damage to piston
and cylinder that would otherwise result from burning the oil
used for lubricating them. Great care must be taken to select
lilbricating oils that will stand even as high temperatures as
those reached in water-cooled cylinder walls. With such
inflammable fuel as gasoline, it is necessary to keep the com-
bustion chamber, the piston head, and the valves reasonably
cool in order to avoid premature explosions due to hot cylinder
walls. These walls are made hot by the high compression
pressures commonly employed with the high-speed, or auto-
mobile, type of engine, as well as by the heat of combtistion.

13. In the majority of automobile engines, the water-
jackets are cast integral with the cylinders, as is shown in
Figs. 1 to 6. However, in a few cases, separate water-jackets
made of sheet metal are successfully used. Examples of such
jackets are to be foxmd in the engines of the Cadillac and Chad-
wick cars. These jackets are lighter than those integrally
cast, because they can be made thinner, and they are not so
liable to be injxired by a freezing of the cooling water. Another
advantage of such jackets is that they can be readily cleaned
when scale deposits accumulate in them.

14. A cylinder of the Cadillac engine is shown in Fig. 7,
which serves to illustrate the separate water-jacket. This
engine is of the L-head type, with all the valves on the right
side of the engine, the cylinders being cast separately. The
water-jacket a, which surroimds the cylinder fc, is made of spun

Digitized by

Google

§ 3 GASOLINE AUTOMOBILE ENGINES 11

copper. The lower end of the jacket is pressed over a flange c
that is cast on the cylinder, and a steel ring d is forced over
the copper, thus clamping the jacket into position and making
a tight joint. The
cylinder head e, con-
taining the valve
chamber, is secured
to the top of the cyl-
inder by a right-and-
left threaded nipple/.
The top of the copper
jacket is clamped
between the cylinder
head and the top of
the cylinder at g and
h, thus forming a
tight joint. The
valve chamber i is
surrounded by water
passages ;, which are
cast integral with the
cylinder head. The
piston is shown at k.
In case of injury to
any part of a cylin-
der of this form, as

for instance to the head, the particular part damaged can be

replaced at the factory without discarding the entire cylinder.

In the six-cylinder engines of the Chadwick car, each pair of

cylinders is sturoimded by a separate copper water-jacket.

AIR-COOLED CTLINDERS

15. The internal construction of an air-cooled cylinder
is the same as that of a water-cooled cylinder; also, the arrange-
ment of the valves and other mechanism is similar. The
external surface of an air-cooled cylinder, however, is extended,
or increased, by various means, usually by the use of thin

Digitized by

Google

12 GASOLINE AUTOMOBILE ENGINES §3

heat-radiating flanges, or ribs, cast integral with the cylinder
walls or fitted to them. These ribs, or flanges, serve to conduct
the heat from the cylinder walls, the heat being absorbed and
carried away by the air that comes in contact with the flanges.

(b)

Fig. 8

In some of the earlier air-cooled engines, the cylinders were
provided with pins, or studs, radiating from the outer surface
of the casting. These studs, which were screwed into the

Digitized by

Google

§ 3 GASOLINE AUTOMOBILE ENGINES 13

cylinder walls were sometimes threaded from end to end in
CMxler to provide a greater heat-radiating surface.

16. The best-known example of the air-cooled cylinder is
that used on the Franklin automobile, which is practically the
only American pleasure car propelled by an air-cooled engine.
Two of these cylinders are illustrated in Pig. 8, a sectional view
of one and an external view of the other being shown in (a) and
a top view of one of these cylinders in (b). Like parts are let-
tered the same in each view. A large heat-radiating surface is
obtained by the use of vertical steel flanges a that are cast in
the wall 6 of the cylinder. The flanges are spaced about i inch
apart around the entire outer circumference of the cylinder and
project radially outwards a distance of about 1 inch. The
average length of these flanges is 8 inches. A cylindrical air
jacket c surrounds each cylinder and, with the cylinder wall,
it forms an air-tight passage through which the cooling air is
drawn. The air is thus brought into close contact with the
flanges, which conduct the heat from the cylinder walls. The
air jackets t: are set in a horizontal metal deck d at the shoulder ^.
This deck forms, with the engine hood and the dash, two sep-
arate compartments, one below and one above. Air drawn from
one compartment to the other must flow through the jacket c
and thus come in contact with the flanges a.

The cylinders shown in Fig. 8 are of the valve-in-the-head
type. The valves/ and g open downwards into the head of the
cylinder and are operated by push rods and rocker-arms. The
valve seats are cast integral with the cylinder head; that is,
no valve cages are used.

17. In the Chase two-cycle engine cylinder, the cooling
flanges are cast integral with the cylinder walls and encircle
the cylinder, being radially arranged on top. This engine is
used principally on motor trucks.

A large radiating surface is obtained in the Duryea two-
cycle engine by fastening copper spines to the cylinders in the
manner shown in Fig. 9. The cylinder is finished inside and
outside. On the outside, the cylinder surface is deeply grooved.
One of these spiral grooves is wider than the other and is intended

Digitized by

Google

14 GASOLINE AUTOMOBILE ENGINES §3

to receive the copper spines a. Both add much to the stiff-
cylinder wall and, without making it heavy, insure
al form. At the head of the cylinder is a small
dch the end of a steel wire is hooked, the other end
ed as shown in Fig. 9 (6), which indicates how the
)ears after the spines are boimd in place, the plain,
cylinder being shown in Fig. 9 (a). The copper
r inch wide, iV inch thick, and about 4 or 5 inches

long. They are doubled
at the middle to fit the
groove into which they
are forced and stand
with both ends project-
ing, each projection being
2 or 2i inches long. The
steel wire is tightly
drawn to bind them in
place. When applied,
this wire is heated, and
^ ^ ^^ as it cools it shrinks and

gnps the copper still
i3 also of such quality that it does not expand
is much as does the cylinder; therefore, the higher
ture the tighter it binds. There is no tendency of
to expand away from the cylinder. The spines
spokes of a wheel, and thus allow ample space for
irculate to the bottom of the grooves. The extra
self allows much additional surface to be reached
The spines are more or less irregular, and thus
offer a variety of paths to the air flowing around them. In
addition to this, copper has the advantage of being a good con-
ductor of heat and therefore the spines form an efficient radi-
ating siuface. The two-cycle engine cylinder is well adapted
to air cooling because the exhaust gases do not heat the head,
but pass out at a point farthest from the head, which is also
cooled from the inside by each new charge thrown against it.
The head has no valve chambers or mechanism to prevent
free access of air to the outside.

Digitized by

Google

§ 3 GASOLINE AUTOMOBILE ENGINES 15

CRANK-CASES

18« General Construction. — ^The casing, or housing,
of an automobile engine that encloses the cranks and crank-
shaft, and, frequently, other moving parts as well, is called
the crank-case. Besides forming a housing for most of the
working parts, it also serves as a frame, or bed, that supports
the crank-shaft and cylinders; and, usually, the lower part
serves as a receptacle for the oil used in the lubrication of the

- Fig. 10

engine. Crank-cases are generally cast of altmiinimi or an
alloy of alimiintim, although in rare cases manganese bronze,
malleable iron, or cast iron is employed. Aluminimi is used on
acxxamt of its light weight in comparison with its strength.
The size of a crank-case depends entirely on the design of the
engine, but in any event it must be large enough to allow the
cranks to rotate freely within it and strong enough to support
the cylinders and crank-shaft.

222B— 13

Digitized by

Google

16 GASOLINE AUTOMOBILE ENGINES §3

Crank-cases are usually divided horizontally into two halves,
which are bolted together. However, they are sometimes
divided vertically, or they are made in single castings provided
with openings for the connecting-rods and for inspection pur-
poses. The type last named is known as the barrel type.

19. Typical Crajik-Cases. — A very common type of
automobile-engine crank-case is that in which the case is divided
horizontally into two halves and the crank-shaft bearings are
supported entirely from the upper half. This type of crank-
case is illustrated in Fig. 10, which shows the upper and lower
parts of the crank-case used on the Premier six-cylinder engine.
In (a) is shown a view of the upper half, such as would be
obtained by a person Ijring on his back beneath the engine
and looking upwards after the lower half is removed. In (b)
is shown a top view of the lower half of the crank-case. There
are four crank-shaft bearings a in this case. The lower half
of each bearing is a cap held in place by capscrews 6, which are
prevented from turning by keepers c; the capscrews are screwed
into the supports d. Movement of the keepers c is prevented
by pins e that extend through the keepers and have cotter pins
passed through them. The object of the keepers is to prevent
the capscrews from turning under the influence df vibration.
The connecting-rod bearing caps / are fastened in the same
manner. The engine is of the T-head cylinder type, the valves
being operated from cam shafts g and fe, which are located on
opposite sides of the crank-shaft.

The lower half of the crank-case is attached to the upper
half by means of bolts that pass through the holes t, and the
entire case is supported from the frame of the automobile by
the arms / and k. The lower half is provided with the oil
troughs /, into which the ends of the connecting-rods dip in
order to lubricate the moving parts of the engine. The bot-
tom m of the case, beneath the oil troughs, is used as an oil
well, or reservoir.

In many cases the oil reservoir is a separate casting bolted
to the lower half of the crank-case, and in a few instances
the lower crank-case is made of pressed steel. Sometimes the

Digitized by

Google

§3

GASOLINE AUTOMOBILE ENGINES

troughs are made of
sheet metal and in-
serted into the lower
half of the crank-case.
Some crank-cases
are made with an
enlarged extension on
one end, which exten-
sion encloses the fly-
wheel.

20« An example
of a crank-case divi-
ded horizontally, but
having its supports
attached to the lower
half, is found on the
Alco car. An exter-
nal view of this crank-
case is shown in
Pig. 11. The upper
and lower halves are
held together by bolts
a, and the entire
crank-case is sup-
ported by the arms 6,
which are cast integ-
ral with the lower
half c. These arms
are connected on each
side by a web d that
serves to stiffen them.
This web also forms a
support for the engine
auxiliaries, such as the
magneto and the
pump, and acts as a
pan to exclude dirt

Digitized by

Google

18 GASOLINE AUTOMOBILE ENGINES § 3

from below. The crank-shaft bearings, which are in line with
the -division line of the case, are supported directly by the lower
half. The flywheel and the dutdh are enclosed within the
enlarged part e.

21. Another example of a crank-case that is supported by
its lower half is illustrated in Fig. 12, which shows a top view
of the bottom half of the crank-case used on the Ford, model T,
automobile. The crank-shaft bearings are carried by the upper
half of the case, which is of cast iron and is cast integral with
the foxir cylinders. The lower half is of pressed steel and is
bolted to the upper half. An inspection plate a is bolted to
the bottom half and can be removed for inspection purposes.

Pig. 12

The rear end h encloses the flywheel and transmission gears
and is supported by two arms c that are fastened to the case.
The front end is supported at a single point d, thus forming
the three-point suspension method of support.

22. A crank-case made of a angle casting and provided
with an opening for inspection is illustrated in Fig. 13, which
shows the crank-case of the Rambler 38-horsepower, foiu:-
cylinder engine. In this case, the opening is in the side, and
it is ordinarily closed by means of a cover fastened on with
capscrews. The interior of the case is divided into two parts
by a partition a that supports the center bearing of the three-
bearing crank-shaft. The end bearings are located at the ends
of the case. In this engine, all the valves are located on the

Digitized by

Google

§ 3 GASOLINE AUTOMOBILE ENGINES 19

same side, the valve-lifter guides being shown at b and the
single cam-shaft at c.

In some crank-cases of this type, for instance, in that used on
the Chalmers '*36*' car, the opening is located at the bottom
and the cover is used as an oil reservoir. The crank-case is
made of a single casting in this instance also. The advantage
of this construction is that it provides a very rigid crank-case,
and hence a good support for the engine.

23. A vertically divided crank-case, such as is used on the
Winton six-cylinder engine, is illustrated in Fig. 14. This

Fig. 13

case, which is made of alimiinum, is divided into two halves,
but the dividing line is vertical and forms right and left halves,
instead of the common upper and lower halves. The crank-
shaft bearings a are mounted in the right half of the case, making
it possible to remove the left half and thus expose the entire
crank-shaft to view without interfering with the adjustment
of any of the bearings. Shallow compartments, or troughs, b
are located beneath each connecting-rod. They contain oil
into which the ends of the connecting-rods dip. Drain holes c
serve as overflows that prevent too high an oil level in each

Digitized by

Google

20 GASOLINE AUTOMOBILE ENGINES § 3

trough. The left half of the crank-case, not shown, is secured
to the right half by means of capscrews that are screwed into
the holes d. The removable half is provided with three hand-
holes that permit inspection without removing the entire half.
The cylinders of this engine are of the L-head type, all of the
valves being operated from a single cam-shaft e.

24. The crank-case of a two-cycle engine must be air-
tight in order that the fresh charge can be compressed in it
before being admitted into the cylinder. There is liability
of leakage through the crank-shaft bearings, and to prevent
this, these bearings should be of suflSdent diameter and length

Fig. U

so that they will not wear out rapidly. Occasionally, two-cycle
engines are provided with stuffing boxes on one or both ends
of the crank-case bearings, and sometimes special forms of
bushings are used with a fair degree of success to prevent leak-
age. In three-port, two-cycle engines, the piston is provided
with a piston ring at its lower end to prevent the gases from
leaking back past the piston into the inlet port.

In multiple-cylinder, two-cycle engines, it is important that
one crank-case should not leak into the other; otherwise, there
would be no crank-case compression. With removable cylin-
der heads, such a condition can be detected by removing the
heads and noting the velocity with which the gas or the air

Digitized by

Google

§3 GASOLINE AUTOMOBILE ENGINES 21

enters the combustion chamber through the passover port
when the engine is turned over.

The crank-case of a two-cycle engine must be as small as
possible, so that the required compression of the fresh charge
may be obtained. The connecting-rod is usually made as
short as possible to attain this object, and in some cases the
vdume of the crank-case has been decreased by providing the
crank-shaft with disks instead of the usual crank-arms. The
disks occupy more space than the crank-arms in the crank-case,
and hence decrease the volume. They thereby increase the
ratio between the voltune of the case when the piston is at the
top of the stroke and the volume when the piston is at the bot-
tom of its stroke, and, consequently, cause a greater degree of
crank-case compression.

25. Craiik-Caae Breathers. — ^The crank-cases of four-
cycle engines are provided with one or more openings to which
are attached pipes, called breathers, that allow the escape of
air and hot gases. With the four-cycle engine, an air-tight
crank-case would not be advantageous, because where the hot
gases leak past the piston rings into the crank-case, there would
be a tendency to overheat the bearings and to bum the oil,
and through imperfect lubrication rapid wear of the engine
would result. The breathers prevent this by allowing these
hot gases to escape. In addition to this, the pressure in a
closed crank-case of a multiple-cylinder engine varies because
of the movements of the reciprocating parts; hence, another
use of the breather is to relieve this pressure variation and
keep it the same at aU tiunes. Varying pressures in the crank-
case might interfere with the proper working of the lubricating
sjTstem by forcing the oil out of the crank-case through the
joints or bearings. Crank-case breathers usually serve the
purpose of oil filling tubes, through which the lubricating oil
is poured into the lower half of the case.

26. Breathers are usually located in the upper part of the
crank-case and are frequently placed on the supporting arms.
Occasionally, they are cast integral with the case, but more
often they are separate pipes bolted on.

Digitized by

Google

Digitized by VjOOQ IC

§ 3 GASOLINE AUTOMOBILE ENGINES 23

An example of a breather pipe cast integral with one of the
sui>porting arms of the engine is shown in Fig. 15 (a). The
web a, which is cast integral with the pipe 6, carries a boss c.
The cover d is supported by a stem e that fits in a hole in the
boss. The lower end of the stem e is slotted, and the two
halves thus formed have a tendency to spring apart and hence
hold the cover in place. The air and hot gases escape between
the edge of the cover and the top of the pipe, as shown by the
arrows. The breather is provided with baffle plates / that are
inclined downwards to prevent the escape of oil with the air.
The oil globules are collected on these plates and rettuned to
the oil reservoir in the bottom of the crank-case. The dome-
like cover also serves to prevent the escape of oil. The breather
communicates directly with the oil reservoir and is provided
with a screen at g for cleaning the oil as it is poured in. The
oil reservoir can be filled by simply removing the cover.

27. Another type of crank-case breather, in which the pipe
is bolted to the crank-case by capscrews, is shown in Fig. 15 (6).
The breather consists of an outer casting a and an inner tube 6,
which is screwed into a partition c in the outer port. The part a
is secured to the side of the crank-case d by means of six cap-
screws, one of which is visible at e. It is provided with a cover/
that is supported by three extensions of the casting, as shown
at g, thus allowing air and hot gases to escape between the cover
and top of the breather. The outer part of the breather is
formed into a lip A, into which oil may be poured. The outer
casting a is in communication with the crank-case proper, and
the inner tube 6 opens into the oil reservoir and is the pipe
through which the reservoir is filled. The oil piunp i is attached
to the breather by capscrews /.

28. A simple form of breather and oil filler is shown in
Pig. 15 (c). It consists of a pipe a secured to the side of the
crank-case 6 by m^ans of capscrews. A funnel-shaped wire
screen c is located in the upper end of the pipe for the ptupose
of straining the oil as it is poured into the case. The cover is
fitted with a second wire screen d that prevents oil from esca-
ping from the crank-case with the air or the gases.

Digitized by

Google

24 GASOLINE AUTOMOBILE ENGINES § 3

29. A common method of attaching a crank-case breather
to the top of the crank-case is shown in Fig. 15 (d). In this

/«oc^ fh^ KtviQ+Vi^r ic cimnKr q Inner ryipQ q enlarged at thc UppCT

it is screwed on. The cap
oil from escaping with the
into the upper part of the
)ject up above the manifold,

y in details of construction
ley are aU used for the same
obtaining the desired result
s, as illustrated in Fig. 15,
show the general design.

3 design of inlet manifolds
nportant considerations are
that the incoming
fresh charge be
equally divided
among the various
cylinders and that
the mixtiu^ going to
the cylinders be of
uniform richness.
These problems are
comparatively simple
with four-cylinder,
four-cycle engines,
because the lengths
of the branches, or
pipes, nmni'ng to the
inlet valves can
easily be made
equal.
The ordinary type
ines having their cylinders

Digitized by

Google

§3 GASOLINE AUTOMOBILE ENGINES 26

cast in pairs, consists simply of a main inlet pipe leading
from the carbureter and two branches leading to the inlet-
valve chambers. The manifdd may be in the form of the
letter T, like that shown in Fig. 16 (a), or it may be in the
fecm of a Y, like that shown in X<&)- The two-branch type of
manifold is possible only in motors having the inlet valves of
adjacent cylinders placed side by side. With engines having
the cylinders cast separately, the manifold is provided with
four branches, and where the cylinders are cast en bloc the
gas inlet sometimes consists simply of a single pipe leading
from the carbureter to the cylinder casting. With a gas inlet
of this type, the charge is distributed to the valves through
passages in the cylinder casting.

31. In the six-cylinder engine of the four-cyde type, the
problem of gas distribution is much more complex than in the

Pic. 17

four-cylinder engine, because of the greater number of valve
chambers to which the mixture must be conducted. The most
efficient form of manifold depends largely on the order of firing
and on the grouping of the cylinders. A simple T-shaped
manifold for a six-cylinder engine having its cylinders cast in
pairs is shown in Fig. 17. It is similar to the T-shaped, four-
cylinder manifold, except that there are three branches leading
to the cylinders, each branch supplying fuel to the inlet valves
of two cylinders.

In some engines, the carbureter is located on the opposite
side of the engine from the inlet valves, and the inlet manifold
extends over the tops of the cylinders. This forms a long inlet
passage from the caii>tu^ter to each valve. In other cases, the
inlet pipe is very short. A short inlet pipe is generally to be

Digitized by

Google

GASOLINE AUTOMOBILE ENGINES

§3

desired on axxxnint of the condensation that is liable to take
place in one of considerable length. Six-cylinder manifolds
are sometimes made Y-shaped or V-shaped, and the pipes are
often curved in order to provide room for accessories. Inlet
manifolds are fastened, to the cylinder castings by capscrews
or by means of yokes and studs. They are most frequently
bolted through a flanged joint to the carbureter. Inlet mani-
folds are generally cast of aluminum, brass, or malleable iron.
Some manufacturers are water-jacketing their inlet manifolds
for part of their length, to assist in vaporizing the fuel and to
prevent condensation, connecting the inlet manifold water-
jacket to the cooling S3rstem of the engine.

32. Exhaust Manifolds. — ^The manifold that conveys the
exhaust gases to the exhaust pipe is usually in the form of a pipe

Fig. 18

of large diameter that communicates- with the various exhaust
ports and is connected in the rear to the exhaust pipe that runs
to the muffler. The manifold usually slopes downwards at an
angle approximating 45° at its rear end, where it is joined to
the exhaust pipe.

In motors having cylinders that are cast separately, one
manifold connection from each cylinder is of course necessary.
With cylinders cast in pairs or in threes, two different arrange-
ments are possible; there may be a single connection for each
cylinder, or there may be a connection for each group of

Digitized by

Google

§ 3 GASOLINE AUTOMOBILE ENGINES 27

cylinders. In the case of T-head motors with cylinders cast in
pairs, a single connection for each pair is customary, although
separate connections are also used. In motors with the cylin-
ders cask en bloc, there may be a single connection for each
cylinder, one for each pair, one for each set of threes, or
simply a single connection to the entire bloc.

A common form of exhaust manifold for a four-cylinder
engine of the T-head type is shown in Fig. 18 (a). The mani-
fold is sometimes provided with longitudinal ribs, as shown,
to help cool it. A manifold for a six-cylinder engine of the
L-head type is shown in Fig. 18 (fc). It has a separate connec-
tion for each cylinder. Those connections are spaced as shown
to allow room for the connections from the inlet manifold, which
is of the three-branch t>'pe.

Exhaust manifolds are generally attached to the cylinder
castings by means of capscrews that pass through flanges,
although they are sometimes secured by yokes and studs. They
are generally made of malleable iron or they are steel castings,
but sometimes they are made of steel tubing.

RECIPROCATING ANB ROTATING PARTS

PISTONS

33. The pistons used in automobile engines are made hol-
low to receive one end of the connecting-rod, which is joined
to the piston by means of a piston pin. Such pistons are of the
so-called trunk type, being coiLstructed in this way so as to make -
a shorter and more compsict engine. The piston consists of a
hollow cylindrical iron casting that is carefully machined in
order to have a good working fit in the cylinder. The diam-
eter of the piston is slightly less than the bore of the cylinder.
If it were the same, the piston would stick when it becomes
heated, because the piston becomes hotter and expands more
than the cylinder, which is kept relatively cool by the water-
jacket. An air-tight joint is made between the-piston and the
cylinder wall by means of piston rings that are placed in grooves
surrounding the piston.

Digitized by

Google

28 GASOLINE AUTOMOBILE ENGINES § 3

34. Piston pins are mounted in the piston in two ways:
they are either secured to the piston casting at each end, the
central part having a bearing in the small end of the connect-
ing-rod, or they are fastened to the upper end of the connecting--
rod and have bearings in the piston casting.

A piston having the pin attached to the casting is shown in
Pig. 19, (a) being an outside view and (fc) a sectional view.
The outside of the piston is provided with three rings a, which
form an air-tight joint between the piston and the cylinder wall.
These rings are parted, as shown at b, so that they can spring

M (b)

Pig. 19

outwards against the cylinder wall and prevent the gases from
escaping from the combustion chamber into the crank-case.
Each of the grooves in which the rings are set, except the lower
one, is made with square comers. The lower comer c of the
groove in which the lower ring fits is beveled to an angle of 45*
instead of being square and thus forms an oil groove, or wiper
groove. The sharp edge of the lower ring, on the downstroke
of the piston, scrapes or wipes all excess oil on the cylinder wall
into this wiper groove, whence this oil is conveyed through
holes to the piston pin to assist in its proper lubrication. This
construction is used in the Northway motors; some other
manufacturers do not use this wiper groove. An oil groove d

Digitized by

Google

§3

GASOLINE AUTOMOBILE ENGINES

is turned on the bottom end of the piston for collecting the oil
that is splashed upwards from the crank-case and distributing
it over the cylinder wall.

The piston pin e is hollow, and it is secured in the piston cast-
ing by means of a setscrew /, which is prevented from backing
out by a short wire that is pushed through a hole in the head of
the screw. The setscrew prevents the piston pin from turning
in the piston and from moving endwise and thus scoring the
cylinder wall. The middle part of the pin e fits in a hard bronze
bushing g in the upper end of the connecting-rod.

35. There are several additional methods of fastening the
piston pin to the piston. Some of these methods are shown in
Fig. 20. In (a) the
pin is held in place
by a locking screw a
that screws into the
boss b of the piston
and extends through
a hole in the hollow
piston pin c. The
locking screw is pre-
vented from un-
screwing very far by
means of a cotter
pin d that passes
through a hole in
the inna: end of the
screw. Insome cases
a nail or a piece of wire is used instead of a cotter pin. Some-
times use is made of two setscrews and a single piece of wire;
the wire is made to pass through the holes in both screws, and
its ends are ttuned back, as shown in (6). In another method,
as shown in (c), the screw passes clear through the piston pin
and the end screws into the boss. The screw in this case is
prevented from backing out by a short piece of wire or a pin
that passes through a hole in its head and strikes against the
inside of the piston. In still another method, as shown in (d),

Pig. 20

Digitized by

Google

GASOLINE AUTOMOBILE ENGINES

§3

the screw is tapered over part of its length. The tapered part
passes through a hole in one side of the piston pin and screws
into a hole in the other side. Screwing up the pin draws the
tapered part tightly in place.

Some pins are held in position by placing a piston ring around
the piston and over the ends of the pin. In other cases, various
kinds of keys are used for keying the pin in the piston bosses.

36. Two sectional views of a piston having the pin secured
to the connecting-rod are shown in Fig. 21. The small end a
of the connecting-rod is spUt and clamped to the middle of the
piston pin by means of a capscrew 6, which passes through the
lugs c. The pin is free to turn in the piston bosses d. The

Pig. 21

piston shown is provided with four piston rings e and two oil
grooves /. All the rings are located above the piston pin.

In some designs, the connecting-rod end is pinned to the pis-
ton pin by means of a tapered pin that is fitted with a nut at one
end. The pin passes through the end of the connecting-rod
and through the piston pin, and is held in place by the nut.

37. The piston pin is usually set as near to the head end
of the piston as possible, leaving just room enough for the
piston rings beyond the piston pin. The object of thus loca-
ting the piston pin is to make the engine as low as possible,
and, in the case of the two-cycle engine, to reduce the size of
the crank-case so as to give a higher compression in the latter.

Digitized by

Google

§3

GASOLINE AUTOMOBILE ENGINES

In two-cyde engines, the shape of the top of the piston is
very important, particularly if the transfer port is located in
the side of the cylinder. The part of the piston that projects
upwards, as shown at a. Fig. 22 (a), and that deflects the incom-
ing charge of gas so that it clears the cylinder of the burned
gases, is called a deflect^
or, or baffle. Instead of
using such a projection,
the piston is in some
cases so shaped as to
deflect the gases in the
same manner; such a
piston is shown in (6).

38. The piston of a
two-cycle engine is
made longer than the
stroke, because other- (a)

wise the exhaust port
would not remain completely covered during the compression
stroke and the gas in the crank-case would escape to the
atmosphere. In three-port, two-cycle engines, a piston ring is
placed at the lower end of the piston to prevent the fresh
charge in the crank-case from escaping past the piston and out
of the inlet port. Such rings are shown in Fig. 22.

Fig. 22

PIfirrON RINGS

39. On accoimt of the mechanical impossibility of making
a solid piston so that it will have an air-tight and at the same
time a free-running fit in the cylinder tmder the conditions
met in automobile practice, elastic, expansible piston rings
made usually of close-grained, gray cast iron, are used to make a
tight joint. For this purpose the piston is grooved and rings
of the form shown in Fig. 23 are sprung, or snapped, into the
grooves. These rings are commonly called snap' rings. They
are split, or cut, in two on one side so that they may have an
expansive elastic action to press them close against the cylin-
der walls. Piston rings are made of such diameter that they

222B— 14

Digitized by

Google

GASOLINE AUTOMOBILE ENGINES

§3

press lightly against the wall throughout their entire drcum-
ference. The joints in the ring where it is spUt are made in

several different forms,
some of which are illus-
trated in Fig. 23.

40. The piston ring
shown in Fig. 23 (a) is of
uniform cross-section, with
the ends lapped at the
parting, as shown at a.
The type of ring is fre-
quently made eccentric;
that is, thinner at the ends
than at the back b. The
parting in the ring shown
in (6) is a diagonal spUt,
as shown at a; it is less
liable to cut or scratch the
cylinder than the one
shown in (a), as no part of
its parting line is parallel
with the motion of the
piston. The parting of
the ring shown in (c) is
also diagonal, but it differs
from that shown in (6) by
having the point a made
square and a notch b
milled in the opposite
comer of the other end,
thus forming a rectangular
space between the ends of
the ring. Into this space
fits a pin that holds the
ring in place in the groove.
A two-piece concentric ring is shown in (d). One ring is placed
within the other, and each ring has a flange that extends over

Digitized by

Google

§ 3 GASOLINE AUTOMOBILE ENGINES 33

the other, closing each opening. This form of ring is known to
the trade as the leakproof ring, A composite ring of the t5rpe
shown in (e) is tised in the Marmon engine. This ring consists
of a heavy, plain, wide ring a, on the outside of which are two
thin rings 6 broken at c on opposite sides and pinned, as shown,
quartering the break in the inner ring. The office of the heavy
inner ring a is to produce the expansive force, while the thin
outer rings conform perfectly to the shape of the cyUnder.
In (/) is shown a sectional piston ring used in some Chalmers
engines. It consists of an outside ring a, which is parted at 6,
and six inner segments c, each of which is provided with a flat
spring d. When the ring is placed in its groove, the springs
force it outwards against the cylinder wall. The outer ring and
the inner segments are of triangular cross-section; hence, when
the springs expand the segments, they tend to sUde on the outer
ring and fill up the groove endwise.

41. Sometimes an additional ring is placed near the open,
or crank, end of the piston. Rings placed in this position are
generally called oil rings. They are supposed to aid in dis-
tributing the lubricating oil over the surface of the cylinder
bore, and also to regulate the amount of oil that passes up from
the crank-case into the combustion chamber. In order to
accomplish this regulation, they are made in diflferent forms
to meet the conditions under which the engine operates with
regard to the amount of lubricant that is splashed, or thrown,
into the open end of the cylinder. In some cases, they are
made with true cylindrical surfaces, in the same manner as
the other rings. In other cases, the outer surface of the ring
is beveled part way across the surface and the ring is put in
place with the beveled side either toward the open end of the
piston or away from this end, according to whether the desire is
to have the ring allow more or less oil to pass by it than in the
case of a ring with a true cylindrical outer surface. The oil rings
also aid in making an air-tight joint and thus in preventing loss
of pressure due to blowing of the gases past the piston. How-
ever, oil grooves are used more extensively than oil rings for
distributing the lubricant over the surface of the cylinder walls.

Digitized by

Google

GASOLINE AUTOMOBILE ENGINES

CONNECTINO-BODS

42. Connecting-rods for automobile engines are usually
made of drop-forged steel and are of I-beam cross-section.
The lower, or crank-shaft, end of the connecting-rod is made
large and contains a bearing for the crankpin; the upper end
is smaller and either forms a bearing for the piston pin or is
rigidly secured to it.

43. A common type of comiecting-rod is shown in Fig. 24
(a). It is of I-shaped section, the large end a being spUt at

(a)

Fig. 24

right angles to the rod through the center of the bearing and
having a bronze or other bearing-metal lining 6. The two parts
of the bearing are held together by the bolts c and d, which pass
through the cap e. The bolts are provided with castellated,
that is, slotted nuts, and cotter pins passing through the bolts
and nuts, to prevent the latter from loosening. The smaller,
or piston-pin, end / is forged solid, then bored out, and a

Digitized by

Google

§ 3 GASOLINE AUTOMOBILE ENGINES 35

bearing metal bushing, usually of bronze, pressed into place,
as shown at g.

A connecting-rod designed so that the small end may be
clamped to the piston pin is shown in (fc). The piston-pin
end is split in the manner shown, a heavy capscrew being used
to draw the parts tightly against the piston pin, which turns
in bearings in the piston casting. The head end forms the usual
crankpin bearing, the halves of which are held together by two
bolts. In some cases the halves of the lower connecting-rod
bearings are held together by means of four bolts instead of by
two.

Fig. 24 (c) shows a hinged crankpin end that is sometimes
used on connecting-rods of automobile engines. The end a
and the cap b are hinged at c, and a bolt d is provided to hold
the parts together.

In the more e;cpensive engines, the piston pin and the bush-
ing are often made of case-hardened steel, and both pin and
bushing are ground to fit.

CBANK-SEULFTS

44. Craiik-slia,fts for automobile engines are made of
special grades or alloys of steel, so that they may be as Ught
as possible and yet be strong enough to resist the twisting
and bending action to which they are subjected, the bearing
part being made suflBdently ample to withstand the wear due
to continuous rotation at high speed. Automobile-engine
crank-shafts are always made in one piece, and are either
machined from a rough flat forging or drop-forged in dies.

45. Crank-shafts for four-cylinder engines are supported
by two, three, or five bearings. A two-bearing crank-shaft is
shown in Fig. 25 (a) ; a three-bearing shaft, in (b) ; and a five-
bearing shaft, in (c). In each case the journals that turn in the
bearings are shown at a, and the crankpins at b. Crank-shafts
for four-cylinder, four-cycle engines are always made in one
of the three forms shown; that is, with the two outer crankpins
in line and the two inner crankpins in line, so that the two
pairs of crankpins are 180° apart.

Digitized by

Google

GASOLINE AUTOMOBILE ENGINES

§3

Crank-shafts for six-cylinder engines are supported by three,
four, or seven bearings. That shown in Fig. 25 (d) is a four-
bearing crank-shaft, and that shown in (e) is carried on seven
bearings. In each case, the journals are shown at a and the

crankpins at b. The cranks are arranged in pairs, one and six
f 6rming a pair, two and five forming a pair, and three and four
forming a pair. The crankpins of each pair are in line, and the
pistons connected to these cranks move in tmison; the several
pairs of crankpins are 120° apart. In the four-bearing crank-
shaft, illustrated in (d), each end crank is connected to the
adjoining crank by means of a dummy journal; in some other
cases, the two crankpins are directly connected by a single
straight arm.

Digitized by

Google

§ 3 GASOLINE AUTOMOBILE ENGINES 37

VALVES AND VALVE MECHANISM

VALVES

46« A poppet valve consists of a disk with a stem at right
angles to the plane of the disk. Poppet valves are used for the
admission of the charge and the control of the exhaust. The
valves open in the direction of the axis of the stems, and are
held to their seats by springs. As they open inwards, they have
no tendency to leave their seats during the explosion, the pres-
sure in the cylinder helping to keep them on their seats. The
valve seats and valve-stem guides may be located in removable
heads or in the cylinder casting.

The valve seats are usually made of cast iron. Nickel steel,
and of late, tungsten steel, has become quite popular for valves
when the head and stem are made in one piece; nickel steel
is also used extensively for the heads of built-up valves
having the stems made of machinery steel. It is claimed that
valves made of nickel steel will neither warp nor scale frgm
excessive heat; in addition, valves made of tungsten steel
seem to be free from pitting. Cast-iron exhaust valves having
steel stems are sometimes used, and also soft steel valves
faced with cast iron welded to the head.

The valve seats are occasionally flat, though more frequently
they are beveled to an angle of 45°. The bevel-seat type of
valve is kept tight more easily than the flat-seat type, and for
this reason it is generally used.

47. A valve that is opened by mechanical force applied by
rigid parts is called a mechanical valve, or, less commonly, a
mechanically operated valve. An exhaust valve of the poppet
type must always be mechanically operated, because it must
be lifted against the pressure in the cylinder at the time the
exhaust is to begin.

The inlet valve, however, can be so constructed as to be
opened by the pumping action of the piston during the suction
stroke. When thus opened it is known as an automatic inlet

Digitized by

Google

38 GASOLINE AUTOMOBILE ENGINES § 3

valve; such valves were formerly used extensively on auto^
mobile engines, but they are now employed in only very rare
instances.

I inlet valve is shown in place
: a rests on the beveled seat b
•ds through the guide d to the
part of the valve stem, how-
ever. The valve spring / is
held in compression between
the guide d and the cap g,
which is held in place by a
collar h with a radial slot
that fits in a groove around
the stem c. As the cam i
turns so that its lobe is
directly under the valve lifter ; ,
the valve is raised against the
compression of its spring and
an opening is formed between
the edge of the valve and the
seat. The valve lifter / by
suitable means is prevented
from turning in the valve-lifter
guide kf and can be adjusted
by screwing the adjusting
screw e up or down. A lock-
nut / prevents the adjusting
screw from turning out of
he top of the valve disk is a
used when grinding the valve,
d in place by means of a key
le valve stem, instead of by a

md exhaust valves, which are
in place in the cylinder head
ts against the flat seat 6 when
/es open downwards into the

Digitized by

Google

§ 3 . GASOLINE AUTOMOBILE ENGINES 39

combustion chamber and are operated by means of the rocker-
arms Cy which, in turn, are operated by means of long push
rods. The valve stem moves in the guide d. Between a
shoulder e on the guide and a cap/, which is screwed on the end
of the valve stem, the spring g is compressed and therefore

Pig. 27

holds the valve to its seat. The rocker-arms act against adjust-
ing nuts h on the end of the valve stem. The cylinder head is
shown cut in half in the illustration so as to show the valves
in place. In this engine, the cylinder head is cast separate from
the cylinder.

VALVE MECHANISM

60. Valve sprlng:s are usually made from steel spring
wire or from soft cast-steel wire, the former being wound cold
and not requiring any heat treatment; when the soft wire is
used, the spring is hardened and tempered after it is formed.
Springs made from spring wire have the disadvantage of becom-
ing set if subjected to hard usage, and hardened and tem-
pered springs are liable to break if not tempered just right.

Helical springs^ or springs wound in the form of a screw thread,
as shown at g, Fig. 27, are used more often than any other on
automobile engines. Occasionally, the springs on inlet and

Digitized by

Google

GASOLINE AUTOMOBILE ENGINES

§3

exhaust valves are made up in the shape of a cone. Such springs
are called cone-shaped springs.

61. The cams for operating the valves of an automobile
engine are usually forged integral with the camshaft, as shown
in Fig. 28. In a few cases, however, they are made separate
and secured to the cam-shaft by means of tapered pins.

Cams vary considerably in shape, or profile, the outline
depending to some extent on the tjrpe of cam-follower , which is

Fig. 28

the part of the valve-lifting mechanism that is in contact with
the cam. An inlet-valve cam designed to be used with a roller
follower is shown in Fig. 29 (a), and the corresponding exhaust-
valve cam is shown in (fe). Another common form of cam,
also used with a roller follower, is shown in {c). In (d) is shown
a cam having rising and falling shoulders a and 6 of convex
form, giving a gradual opening and closing. This form of cam
is used with a mushroom, or flat-bottomed, cam-follower.

62, If the inlet and exhaust valves of an automobile engine
are located in the sides of the cylinders, they are usually oper-

PiG.29

ated directly from cams acting on valve lifters, which are
placed between the cams and the valve stems. There are
various designs of valve lifters; some are flat where they rest
on the cams, others are rounded off, and still others are pro-
vided with rollers at the bottom end. The majority of makes
of valve lifters are provided with some means of adjusting their
length; usually an adjusting screw is placed in the upper end.

Digitized by

Google

§3

GASOLINE AUTOMOBILE ENGINES

53. A simple form of valve lifter is shown in Fig. 30 (a).
It cxwisists of the solid cylindrical part a, which has-a flat lower
end fc, thus forming a large bearing surface for the cam. The
tipper end of the valve lifter supports the valve stem c. No
means of adjustment is provided for this lifter, but the valve
stem c may be lengthened by drawing it out as shown by the
dotted lines d. The valve lifter shown in this view is used on
the Ford, model T, engine.

Another simple form of valve lifter is that shown in view (fc).
It is used on the Maxwell four-cylinder, 25-horsepower engine.
The entire lifter is made
of pressed steel. The body
a is cup-shaped and is
pressed with square cor-
ners at the bottom, thus
forming a large flat con-
tact surface for the cam.
The top part 6 of the lifter
is threaded and screws
into a; hence, the length
can be adjusted by turn-
ing the squared end c, A
lodcnut d is provided to
prevent the part b from
jarring out of adjustment.

64. A valve lifter of *^^ <^>
the rounded type is shown '^^- 30

at y. Fig. 26. Instead of being fitted with a roller or having a
flat contact surface, the lower end of the lifter is made rect-
angular in shape and rounded off. With a lifter of this type,
some means must be provided for preventing it from turning
in its guide and getting out of alinement with the cam. In the
example shown, the guide k is slotted and the rectangular part
of the lifter extends into the slots, thus keeping it in line with
the cam.

65. The roller type of valve lifter, several forms of which
are shown in Figs. 31 to 33, is very extensively used.

Digitized by

Google

GASOLINE AUTOMOBILE ENGINES

§3

Two adjacent lifters used on the Northway engine are illus-
trated in Fig. 31, which shows an external view of one and a
sectional view of the other. On account of operating different
valves, these lifters are in different positions, but they are
exactly alike and similar parts are lettered the same in the two
views. The body a of the lifter is slotted at the lower end to
receive a roller 6, which is carried by the pin c. The roller is
kept parallel with the cam by means of a slot d in the guide e,
into which the roller extends. As the valye lifter is raised and
lowered by the cam, the roller is guided
by the slot in the guide and hence does
not move from its correct position on the

Pig. 31

Fig. 32

cam. This valve lifter is made adjustable by means of the
adjusting screw /, which can be screwed up or down as required.
The locknut g prevents the screw / from being jarred out of
adjustment. Washers h and i are placed between the nut g
and the upper end. of the lifter. The guide e is held in place
by the flange formed on it, which is clamped between the
cylinder casting and the crank-case.

Digitized by

Google

§ 3 GASOLINE AUTOMOBILE ENGINES 43

56. Another valve lifter that operates on the same prin-
ciple as the lifter just described is shown in longitudinal sec-
tion in Fig. 32. An

important feature
of this lifter is that a
fiber block a is set
in the upper end of
the adjusting screw 6
to deaden the sound
produced by the end
of the lifter striking
the end of the valve
stem. The roller c
moves up and down
in the slotted guide
rf, which prevents it
from coming out of
alinement with the
cam. The guide is
made of bronze, and
is held in place by
stud bolts e. This
type of lifter is used
on the Pierce-Arrow
engine.

57. In Fig. 33 (a) \
is shown the valve
lifter used on the
Buick engine. It dif-
fers slightly from the
preceding. Two ad-
jacent lifters are
shown with the yoke

a in place for holding ^'^* ^

the guides 6 in position. In this form of valve lifter, the ends
of the roller pin c extend beyond the lifter d and work in nar-
row slots e in the guide &, thus keeping the roller in alinement

Digitized by

Google

44 GASOLINE AUTOMOBILE ENGINES § 3

with the cam. The lifter is made hollow in order to lighten
it and to receive the end / of the push rod, which in this case

is used to operate
overhead valves.

Two adjacent
valve lifters used on
the Beaver engine
are shown in differ-
ent positions in
Pig. 33 (fe). In this
lifter, the roller a is
held parallel with the
cam by means of a
pin b that passes
through the lifter
and extends into
slots c in the guide d.
Adjustment is made
by means of the com-
mon form of adjust-
ing screw and lock-
nut. The guide is
held in place by the
cyhnder casting and
the crank-case.

58. In some en-
gines it is the prac-
tice to make use of a
cam-lever placed
between the cam and
the end of the valve
lifter, as shown at a,
Pig. 34. The purpose
of this lever is to
eliminate, as far as
i lifter. The lever is
middle a roller b that

Digitized by

Google

§ 3 GASOLINE AUTOMOBILE ENGINES 45

follows the cam c. The side thrust of the cam is therefore taken
by this roller and by the lever a, and is not transmitted to the
lifter d. The lever is so arranged that it it is at right angles
to the lifter when the valve is raised half way. The type of
cam lever here illustrated is used in the Rutenb^ motor.

69. Poppet valves loca-
ted in the cylinder head and
opening downwards are ope-
rated by means of tappet
rods and levers, as shown in
Fig. 36, which illustrates the
method used in the engine of
the Franklin car. The lever
a is pivoted at 6 and is ope-
rated by means of the tappet
rod c. The rod c is raised by
means of a lifter d that moves
in a guide e and that in turn
is raised by the cam /. A
spring g at the base of the
tappet rod keeps the lever a
constantly in touch with the
valve stem and prevents
clicking. The mechanism is
adjusted by means of an
adjusting screw fc, which is
prevented from backing out
by the locknut i. The tap-
pet rod is yoked at its top
end and fits over the end of
the lever a. ^""'^

In modem engines, the valve stems and springs are covered
by a removable housing, excepting in case of overhead valves.

60. Three methods of driving the cam-shaft and the cir-
culating pimip and magneto shafts are illustrated in Figs. 36
to 38. Gears or silent chains, or a combination of both, are
located at the forward end of the engine, and they connect

Digitized by

Google

46 GASOLINE AUTOMOBILE ENGINES § 3

the crank-shaft with the various auxiliary shafts. The gears
or chains are enclosed in a casing, one part of which is usually

Pig. 36

cast integral with the crank-case. The front part is made in
the form of a cover-plate and is removable.

61. Fig. 36 shows the timing gears used on the White

Fig. 37

40-horsepower engine. The cam-shaft gear a is driven from the
crank-shaft gear b through the idler c. Gear a has a diameter

Digitized by

Google

§ 3 GASOLINE AUTOMOBILE ENGINES 47

that is twice that of &; hence, its speed is one-half that of the
crank-shaft, as is reqtdred for a four-cycle engine. The magneto
shaft d is also driven through the idler and rotates at crank-
shaft speed. The pump shaft is driven by the small gear e,
which meshes with the cam-shaft gear a. Helical gears are
used in order to eliminate noise as much as possible. The
removable cover is attached by capscrews and bolts that pass
through the holes/.

In Fig. 37 is shown the silent-chain drive arrangement used
on Cadillac engines. The cam-shaft is driven at one-half

Fig. 38

crank-shaft speed by the silent chain a running on sprockets 6
and c, and the motor-generator and circulating-pimip shaft
is driven by the chain d running on the sprockets b and e. The
motor-generator is an electrical machine used for cranking the
engine and lighting the car.

A combination drive consisting of helical gears and a silent
chain is shown in Fig. 38. The cam-shaft is driven from the
crank-shaft by a gear a that meshes with a gear on the crank-
shaft. The magneto shaft is driven by the gear b meshing
with the cam-shaft gear. A silent chain c connects the crank-
shaft with the electric starting device shaft. This chain also

222B— 15

Digitized by

Google

48 GASOLINE AUTOMOBILE ENGINES § 3

drives the circulating pump and the commutator shaft. The
cover is fastened on by means of capscrews. This arrangenient
is used on engines built by the Continental Motor Company.
The chain c is lubricated by running in a bath of oil.

rriNGS Aia> engine rating

PBIMINO CUPS

means of which an engine may be primed
► the combustion chamber, and which may
eve the compression, is shown in Fig. 39.
lar plug a carefully groimd to fit the taper-
2t in which this plug is turned by means of
the handle h. The cup c is suflBdently
large to hold the required amoimt of gas-
oline for the priming charge when the
engine is to be started. The plug a is
held in place by a phosphor-bronze
spring d placed between two washers e
and /, and a pin g serves to hold the
whole together. The tension of the
spring d is suflSdent to hold the plug
firmly in position and to take up wear,
thus preventing loss of compression by
leakage. The spring also serves to keep
• heavy vibration. In using this plug, the
: is poured into the cup c and the cock a
ermit the gasoline to flow into the cylinder
[ine is started or during the suction stroke,
also used for introducing kerosene or any
tnce into the cylinders for the piupose of
a deposits.

AIR-PRESSUBE PUMPS

gasoline tank is located at a relatively low
lobile, as, for instance, at the rear of the
le body line, the gasoline is forced to the

Digitized by

Google

§ 3 GASOLINE AUTOMOBILE ENGINES 49

carbureter by means of pressure maintained in the tank. This
pressure in most cases is produced either by a hand-driven
pump or by a power-driven pump that is driven from the
engine.

64. Two engine-driven air pumps are illustrated in Fig. 40.
A perspective view of the air-pressure ptunp used on the North-
way motor is shown in (a). The cylinder a is of cast iron and
is bolted to the side of the crank-case by means of the flange 6.
The piston c is operated by one of the exhaust-valve cams,
which bears against the follower d. The follower is kept in
contact with the cam by the spring e. As the cam rotates,

ra> (b)

Pig. 40

the piston moves in and out of the cylinder a. When the pis-
ton imcovers the ports / drilled in the cylinder wall, air is taken
in, and as the cam rotates the piston is forced inwards, com-
pressing the air and driving it out of the delivery pipe g. An
adjustable check-valve is located at fe, and the amount of pres-
sure carried in the gasoline tank may be varied by screwing
this adjustment in or out, as may be riequired.

65. A cross-sectional view of the air pressure pump used
on the Steams-Knight engine is shown in Fig. 40 (&). The
cylinder a is bolted to the crank-case, as shown, and the piston b

Digitized by

Google

60 GASOLINE AUTOMOBILE ENGINES §3

is driven through the connecting-rod c from one of the sliding-
sleeve connecting-rods of the engine. On the outward, or suc-
tion stroke of the piston 6, the air enters the cylinder a through
a groove at the top, and on the inward, or compression, stroke
the air is forced out through check-valve e and outlet pipe /.
The pressure to which the air is compressed may be varied
by screwing the adjustable head g in or out, as desired. The
head is kept in any adjustment by means of the locknut h. A
plug is screwed into the opening shown at d, and is removed
to drain excess oil from the cylinder.

The pressure to which these ptunps compress the air is gen-
erally from i to 3 poimds, although it may be varied at will
by means of the adjusting device.

HORSEPOWER RATING

66. Gasoline automobiles are rated in the United States
according to the horsepower of the engine. This horsepower
is calculated by means of a formula called the A. L. A. M. for-
mula and also the S. A. E. fonuula, which is so named
because it was adopted by the Association of Licensed Auto-
mobile Manufacturers and afterwards by the Society of Auto-
mobile Engineers for calculating the rated horsepower of a four-
cycle gasoline automobile engine. The formiila does not give
the exact power delivered under every condition nor the exact
theoretical horsepower, but it offers a means of comparison
between different engines. It is based on a piston speed of
1,000 feet per minute, an average pressure in the cylinder of
90 pounds per square inch of piston area, and a mechanical
efficiency of 75 per cent. The A. L. A. M. formiila is as follows :

H.P. = ^,
2.5

in which H . P. = horsepower ;

-D = cylinder diameter, in inches;
A/'=nimiber of cylinders.

Expressed in words, the horsepower of a four-cycle gasoline
automobile engine is equal to the diameter of the cylinder, in

Digitized by

Google

§ 3 GASOLINE AUTOMOBILE ENGINES . 51

inches, multiplied by itself and by the number of cylinders,
and the product divided by 2.5.

For example, the rated horsepower of a four-cylinder, four-
cycle engine having a bore of 5 inches may be found by this
formula as follows:

H.P. = ^,
2.5

in which Z>=5;

Therefore H.P. = — -

2.5

_25X4
2.5

2.5

Hence, the horsepower of the engine is 40.

For two-cycle engines, the horsepower may be taken as
approximately 1.65 of that of a four-cycle engine of the same
dimensions calculated by the formula just given. From the
fact that there are twice as many explosions per minute in the
cylinder of a two-cycle engine as in the cylinder of a four-
cycle engine running at the same speed and having the same
dimensions, it might be supposed that the power developed
would also be twice as great instead of about 1.65 times as
great. However this is not the case because of certain features
of the two-cycle engine that tend to lower its horsepower out-
put and cause it to vary more than that of the four-cycle
engine. These are, usually, lower compression and lower mean
effective pressure due to inefficient scavenging, or cleaning, of
the cylinders after each working stroke. There are, of coiu-se,
exceptional cases where the output of a two-cycle fengine is
nearly twice that of a four-cycle engine of the same dimen-
sions but the ratio given is usually considered as the average.

67. The horsepower of four-cycle engines having from one
to six cylinders and a bore varying from 2^ inches to 6 inches,
as computed by the A. L. A. M. formula, is given in Table I.

Digitized by

Google

GASOLINE AUTOMOBILE ENGINES

§3

TABLE I

HOBSBPOWBB BT A. L. A.

M. FOBmJLA

Bore

Horsepower

Inch

MiUi-

One

Two

Four

Six

meters

Cylinder

Cylinders

2-5

• 500

10.00

1500

2.81

5.61

11.23

16.83

302

6.04

12.08

18.13

3-34

6.68

1337

20.00

360

7.20

14.40

21.60

3.92

783

15.64

2350

4.22

8.45

16.92

2539

456

9.12

18.21

27.30

4.91

9.82

19.61

29-45

527

10.53

21.08

31-57

5-62

11.25

22.50

33-75

3i .

6.05

12.11

24.22

3632

102

6.40

12.80

25.60

38.40

105

6.80

1360

27.20

40.80

108

7-25

1450

29.00

43-50

III

765

1532

3065

46.00

114

8.10

16.20

32.40

48.60

118

8.57

17.14

34.28

51.41

121

905

18.10

36.15

54.20

124

9-55

19.12

38.25

57-21

127

10.00

20.00

40.00

60.00

130

10.55

21.10

42.20

6330

133

11.04

22.10

44.20

66.40

137

"•59

2318

46.34

69.50

140

12.12

24.24

48.48

72.72

143

12.68

2538

50.80

76.10

5i '

146

1325

26.50

5300

7950

149

13-81

27.62

55-28

82.88

152

14.42

28.53

5770

86.64

Digitized by

Googk

AUTOMOBILE-ENGINE
AUXILIARIES

COOLING, MUFFLING, AND GOVERNING

COOLING SYSTEMS

INTRODUCTION

1. In an internal-combustion engine, unless provision were
made for cooling, the heat from the explosion of the charge
would raise the temperature of the cylinder walls and piston
so high as to render lubrication impossible. The devices
employed for cooling purposes comprise what is known as the
cooUng system of the automobile.

Most automobile engines are cooled by circulating water
through the space between the outer wall of the cylinder and
a jacket casing that surrounds the cylinder head and the part
of the cylinder barrel nearest, the head. Air is used for cooling
in only a comparatively small proportion of automobile engines.

About the only objection to the use of water for cooling is
that it is liable to freeze in cold weather. In order to over-
come this objection, however, various substances are added
to the water or dissolved in it so as to form a mixture that will
not freeze until the temperature is considerably below that at
which pure or nearly pure water freezes.

2. When water is used for cooling, it enters the jacket
space generally either at its lowest part, or just below the

COPYNIOHTBD 0Y INTERNATIONAL TEXTBOOK COMPANY. ALL illOHTS RBBBRVBD

§4

^ t J^ ^ ' ' •-' ' ^'^i^'z^cl b;

yGoogk

2 AUTOMOBILE-ENGINE AUXILIARIES §4

exhaust valve, and flows out at the highest part. It is extremely
important to have the water flow from the highest part of the
jacket space, because an air pocket or steam pocket would be
formed if a part of the enclosed space were higher than the
outlet. It is also very important that the jacket space should
be shaped so that there is no part from which the water cannot
flow upwards toward the outlet.

The hot water from the jacket passes through connecting
pipes to a radiator^ where it is cooled, and from the radiator
it passes back to the jacket space of the engine again. It then
repeats its cycle of cooling the engine and being cooled in the
radiator. Circulation is maintained either by a pimip, which
forces the water through the system, and which on this account
is called a forced-circulation system, or by what is known as
thermal circulation, which means circulation due to the heating
of the water.

WATER COOLING

3. Forced-Circulation Cooling System. — In Fig. 1 is
shown the water-cooling system of the Studebaker "20" car,
which system serves well to illustrate the tjqjical arrangement
of the cooling-system parts in automobiles using monobloc
cylinder castings, and having the engine at the forward end of
the car, as is now the tmiversal practice. In order to show the
cooling system clearly, part of the water-jacket is broken
away and the radiator, as well as the pump, is illustrated in
section. The cooling water passes from the top of the water-
jacket a surrounding the upper end of the fotu* cylinders through
a flexible hose connection b to the upper tank c of the radiator;
it then passes downwards through the radiator tubes d, which
are surrounded by horizontal fins soldered to them, to the bot-
tom tank e of the radiator. This bottom tank e is connected
by a pipe, which cannot be seen in the view given, to the casing
of the circulating pump/, which pimip is driven from the engine
cam-shaft and delivers the cooling water through the pipe g
to a manifold h attached to the bottom of the water-jacket.
This manifold has two outlets into the water-jacket in order
to insure a better distribution of the cooled water than is

Digitized by

Google

§ 4 AUTOMOBILE-ENGINE AUXILIARIES 3

possible with a single outlet. The fan i, which is rotated at a
high speed by the engine, draws air over the tubes d of the
radiator and their surrounding fins, thereby abstracting heat
from the cooling water; that is, cooling it.

4. With an engine having monobloc cylinders, as shown
in Fig. 1, a single outlet from the top of the water-jacket is
usually sufficient. When the engine has individual cylinders
or twin cylinders or triple cylinders, there must be a manifold

Fig. 1

to convey the cooling water to and from the water-jackets
of the cylinders. This is clearly shown in Fig. 2, which illus-
trates the water-cooling system of a six-cylinder Packard car.
In the engine of this car, the cylinders a are cast in groups of
two; hence, there are three top outlets b from the water-jackets,
the outlets being connected to each other by hose connections c
and finally to the top of the radiator d by a hose connection e.
Instead of connecting the outlets from the top of the water-

Digitized by

Google

4 AUTOMOBILE-ENGINE AUXILIARIES §4

jackets with rubber hose, as is done in the Packard engine
illustrated, many manufacturers use a metallic manifold with
the piping and outlets cast or otherwise formed as a single
piece ; the final connection to the radiator is made with a rubber
hose, however.

The hot water coming from the top of the water-jackets
flows through the upwardly inclined manifold into the top
water tank of the radiator and passes downwards through
numerous narrow water passages into the bottom water tank
of the radiator, from which it passes through an elbow / and

Pic. 2

a hose connection g to a circulating pump h and thence past
a hydraulic governor i to the manifold ;, which has three
branches, one leading to the bottom of the water-jacket of
each cylinder casting. The hydraulic governor i, although
inserted in the water-cooling system, has no connection with
the cooling of the engine; its purpose will be explained in the
proper place. In order to aid in cooling the water passing
through the radiator, a fan k driven by a belt / from the engine
draws air through the square openings between the water pas-
sages joining the top and bottom tank of the radiator. A
drain cock m is placed at the lowest point of the water-cooling

Digitized by

Google

§ 4 AUTOMOBILE-ENGINE AUXILIARIES 5

S3rstem; when this cock is opened, all water can be drained
from the system.

The carbureter used with the Packard engine here illustrated
is water-jacketed in order to keep it warm and thus aid vapor-
ization of the gasoline; hot water is taken from the cooling
system through the pipe n txom the top of the water-jacket
of one pair of cylinders. This water cools somewhat in passing
downwards through the carbureter jacket and is discharged
through a pipe o into the engine-cooling system directly above
the water-circulating pump h.

The water system of a water-cooled engine is filled through
an opening on top of the radiator, and this opening, when not
in use, is closed by a filler cap, as shown at p.

5. Thermo-Siplion Cooling Systems. — ^Although most
automobile manufacturers seem to prefer to use the forced-
circulation system of water cooling, there are some who use
successfully the thermal system, or as it is better known, the
thermO'Siphon system of water cooling. This cooling system is
characterized by the absence of a circulating pump, the cir-
culation being established and maintained by heating the water
to a higher temperature in the water-jacket of the cylinders
than in the remainder of the cooUng system. Inasnmch as
hot water is lighter than cold water, it tends to flow upwards;
conversely, cold water is heavier than hot water and tends to
flow downwards.

6. The most widely known example of a thermo-siphon
cooling system is found in all Ford, model T, cars having a
manufacturer's number higher than 2,500. Cars of this model
bearing a lower number were fitted with a forced-circulation
system.

The radiator consists of an upper tank a. Fig. 3, and a lower
tank b tmited by a lai^ge number of vertical tubes supplied with
horizontal cooling fins. The water-jacket c surrounds the
upper part of the four cylinders, which, together with the upper
half of the crank-case, are a monobloc casting. The heated
water passes from the water-jacket through the upwardly

Digitized by

Google

Drougnx aooui in xne same manner as m xne rora car, ana is
shown by the arrows. A fan d driven by the engine assists
the cooling of the water by drawing air through the radiator.

Digitized by

Google

§4

AUTOMOBILE-ENGINE AUXILIARIES

8. In the thermosiphon cooling system employed first
in the Renault car, which system has since been adopted by
several other manufacturers, the radiator, instead of being
placed on the chassis in front of the engine, is moimted back
of the engine; that is, just in front of the dashboard. Three
views of the Renault cooUng system are shown in diagram-
matic form in Fig. 5. The radiator a consists of the usual
top and bottom tanks, which are united by numerous plain
vertical tubes. The top of the cylinder water-jackets is con-
nected to the top radiator tank by the manifold 6; the bottom
of the water-jackets is connected by the manifold c to the bot-
tom radiator tank. Circulation of the cooling water is estab-

PlG. 4

lished and maintained in the manner explained in Art. 6.
The engine is enclosed by the hood d, which has sloping sides
and a sloping top and front; this hood extends backwards to
the radiator. The bottom of the engine is protected by the
sod pan e, which, like the hood, is closed at the front end and
open at the rear. No separate fan is employed to draw air
through the radiator; the flywheel/, however, is cast with vanes
on its outside, and these drive air to the rear. The circulation
of air through the radiator is as follows : Air enters at the sides
of the radiator, as shown by the arrows g, and also at the front
through the part of the radiator that is not covered by the
hood d, as shown by the arrows fe. This air passes from both

Digitized by

Google

t* i

Digitized by

Google

§4 AUTOMOBILE-ENGINE AUXILIARIES 9

sides of the radiator toward the central part covered by the
hood and then forwards imder the hood, as shown by the
arrows i\ the air then passes downwards under the hood, as
shown by the arrows ;', past the flywheel, and out at the rear
of the sod pan, the circulation being kept up by the vanes of the
flywheel.

9. In a thermo-siphon cooling system, the opening through
which the water from the engine enters the upper radiator tank
should not be located above its bottom. If this is done, the
circulation will stop as soon as the level of the water falls below
the bottom of the opening, even if a considerable amount of
water is still retained in the tank and the upper ends of the cool-
ing tubes are covered with water to a considerable depth. The
proper place to connect the pipe coming from the top of the
water-jacket is at the bottom of the upper tank, as shown in
Fig. 3.

In all cases, the cooling system should not be air-tight, but
should have an orifice or, overflow^ above the normal level of
the water to allow the escape of air, water, or steam. The
water expands by heating, and in case it boils, steam is formed.

10. Tyi)es of Radiators. — ^As previously explained, the
cooling water heated in the water-jackets of the engine is cooled
by passing it through a radiator. In order to cool the water
effectually, radiators are usually made of thin metal, with as
much surface exposed to the air as possible, and they are
arranged so that the air can circulate through them easily.

There are two general types of radiators, which are named
in accordance with their construction. One of these types is
spoken of as the tubular radiator, the cooling being done by
passing the heated water through round or flat tubes around
which air circulates to abstract heat and carry it away. The
second type is known as the cellular radiator, from the general
resemblance it bears to a mass of cells; in this type of radiator
the water to be cooled surrounds the cells and the air that
abstracts and carries away heat passes through the cells.

Radiators are always mounted at right angles to the frame
of the car, and usually in front of the engine, although some

Digitized by

Google

DMOBILE-ENGINE AUXILIARIES

§4

them at the rear of it. As a general rule radiators
. some cases radiators, when viewed from above,
nth the apex to the front, or are slightly roimded ;
ons are adopted only in order to give a distinctive
the front of the car.

sir radiators nearly always have the tubes sur-
large number of thin fins, or gills, that are sol-
dered to them, the object
of these fins being to in-
crease the radiating surface
to an extent sufficient to
produce satisfactory cooling
of the water.

Radiators of the tubular
type may be divided into
two general classes; name-
ly, (1) radiators in which
each tube has its own fins,
and (2) radiators in which
the fins are common to all
the tubes. At one time ra-
diators belonging to the first
class were very extensively
used, but of late years radi-
ators of the second class
have displaced them to a
large extent.

12. Tubular - Radla-
% tor Construction. — Ra-

^ diator tubes with individual

^^ fins are made in two ways,

^c. 6 as is clearly illustrated in

5W (a) is presented a plain radiator tube, in

a are circular, being pimched from sheet metal.

inese nns are strung over a circular tube 6, after which the

tube and fins are dipped into molten solder in order to solder

them together. The disks, or fins, are made in various ways.

Digitized by

Google

§ 4 AUTOMOBILE-ENGINE AUXILIARIES 11

Sametimes they are simply plain, like washers, in which case
their attachment to the tube is rather flimsy; sometimes a col-
lar is formed on the disks, as shown at (b) ; and some makers
punch the center of the disk in such a way that triangular lugs
are formed, as shown at (c). Either of the methods shown
in views (6) and (c) permits the fins to be attached to the tube
in a substantial manner.

In view (d) a part of a Long spirally wound radiator tube is
shown. In this radiator tube, the fin is continuous, being
formed from a flat strip of copper that is crimped in such a
manner that it can be wound spirally around the central tube,
as shown.

13« Radiators having
tubes with individual fins
were at one time made up
in the form of coils, the
tubes running horizontally
and being connected by
return bends in such a
manner as to form a con-
tinuous tube, with the cool-
ing water entering at one
end and leaving at the other.
This method of construction
is obsolete, however.

In modem practice, when tubes with individual fins are
employed, the tubes are placed vertically between a top and a
bottom water tank and each tube is independent of the other.
The appearance of such a radiator is shown in Fig. 7, which
presents a front view. In this illtistration, a is the top water
tank, b the bottom water tank, c the filler opening closed by a
removable cap, and d are lugs by which the radiator is supported
on the side members of the frame of the car. In some cases
the lugs are at the rear of the radiator. In no case do the
sides form water connections between the top and bottom
tanks. The part of the radiator between the two tanks and
sides is commonly called the radiator core.

2223—16

Digitized by

Google

12 AUTOMOBILE-ENGINE AUXILIARIES §4

which a comparatively small pig. 9

number of flat vertical tubes are used is shown in section in

Fig. 10. The tubes a are placed with their narrow sides to

Digitized by

Google

§4 AUTOMOBILE-ENGINE AUXILIARIES 13

the front and the rear, and are soldered into the bottom of the
top tank b and into the top of the bottom tank c. The tubes
form the water passages in which the water passes downwards,
air circulating aroimd them. The two sides of the radiator,
as d, for instance, do not form water passages. A nozzle e
is attached to the rear of the top tank and is connected to the
pipe leading to the top of the engine-cylinder water-jackets.
In some cases the tubes are left plain; in other cases, fins of
various kinds are soldered to
the tubes in order to increase
their radiating surface. One
way in which the surface is
extended is shown at /; a flat
strip of sheet metal is punched
and corrugated, as shown, and
is soldered to one or both sides
of the tubes. The corrugated
strips then extend the whole
length of the tubes. Some-
times a false front, made as
indicated at g, is fitted into
the front end of the radiator
in order to convey the impres-
sion that the radiator belongs
to the cellular type, which is a
far more expensive form.

An angle h made of sheet
metal is usually attached to the
rear of the top tank and to the
rear of the two sides, forming ^*<=- ^°

a ledge for the hood over the engine; this angle is known as a
hood ledge. To prevent rattling of the hood on the hood ledge,
this ledge is usually perforated and a strip of rawhide belt
lacing or some similar material is fastened to its outside. An
overflow pipe, whose opening is at i, is usually attached to the
upper tank and led along the back of the radiator to a point
below the upper end of the lower tank; its lower end is open.
This overflow pipe prevents filling the radiator too full, and

Digitized by

Google

14 AUTOMOBILE-ENGINE AUXILIARIES §4

also provides for free expansion of the cooling water on becoming
heated.

<c) (d)

Pig. 11

agonal cross-section that are laid side by side in such a manner
that there is a water space aroimd them. In another widely
used construction, sheets of metal are bent to form cells that
have water spaces arotind them when suitably assembled
It is urged in favor of the individual-tube construction that,

Digitized by

Google

§ 4 AUTOMOBILE-ENGINE AUXILIARIES 15

in case of leakage, repairs can be executed with great facility
by any one expert in the use of a soldering iron, as a tinsmith,
for instance.

17. In the Fedders cellular
radiator, individual copper
tubes, either A or i ^^ch
square, are employed. These,
as shown in Fig. 11 (a), are
enlarged at both ends and are
assembled either staggered, as
shown in (6), or in straight
Unes, the ends being soldered fig. 12

together. A cross-section through a few tubes of a stag-
gered assembly is presented in {c)\ this view clearly shows
the tortuous water passages formed by staggering the tubes.
When a staggered-tube assembly is used, it is generally placed
so that the straight water passages a are horizontal, thus forcing
the water to follow a zigzag path in passing downwards through
the radiator.

A cross-section through a tube assembly in which the tubes
are set in straight lines is shown in {d). Here, the water pas-
sages are in line both vertically and horizontally, and hence the
water passes downwards through the radiator in straight lines.
This arrangement of the tubes permits a freer water circula-
tion, but is not so efficient, as far
as cooling the water is concerned,
as the staggered-tube assembly.

The water spaces are about
^ inch in width and about 3 J inches
deep, the individual tubes being
about 4 inches long.

In Fig. 12 is shown the appear-
ance of a complete Fedders radia-
FiG. 13 tor using the straight-line tube

arrangement, the particular radiator illustrated being used in
the Winton car. The radiator is supported on the side mem-
bers of the frame by the two lugs a.

Digitized by

Google

16 AUTOMOBILE-ENGINE AUXILIARIES § 4

18. When hexagonal tubes are used in the construction
of cellular radiators of the individual-tube tjrpe, these tubes
are enlarged at the ends in the same manner as square tubes;
the individual tubes are then nested, as is shown in Fig. 13,
so that the tubes lie in horizontal rows. When thus nested,
the water spaces, shown black in the illustration, between
adjacent tubes in the horizontal rows are vertical, and a bet-
ter water circulation is instu-ed than is possible if the tubes

Fig. 1

are nested so they are staggered. As an inspection of Fig. 13
shows, a cross-section of the tubes greatly resembles a honey-
comb; this resemblance has led to calling this type honeycomb
radiators. Strictly, the term honeycomb radiator should be
appjied only to those constructed with hexagonal individual
tubes nested as shown; it is common practice, however, to
apply the term to all cellular radiators.

Digitized by

Google

§ 4 AUTOMOBILE-ENGINE AUXILIARIES 17

19. Celltilar radiators in which the cells are formed by
bending long strips of sheet metal, usually sheet copper or
sheet brass, frequently have their cores made from strips bent
as shown in Fig. 14 (a). These strips have a width equal to
the desired depth of the radiator core, and are assembled as
shown in (6), thus forming vertical water spaces ranging from
A to t*^ inch in width and having a depth about J inch less
than the depth of the core. The ends of the water spaces are
closed by soldering. The construction shown is employed in
the Mayo radiators.

Pig. 15

Radiators constructed as shown in Fig. 14 naturally do not
have 90 much cooling surface per tmit of area as cellular radi-
ators with individual tubes, since there are no horizontal or
inclined water spaces joining the vertical water spaces.

20. The radiator core used in the Livingston radiator is
bent up from strips of sheet metal in such a manner,, and is so
assembled that it overcomes the objection mentioned in Art. 19 ;
in this radiator core, the water spaces surroimd the four sides
of each cell, which is square in cross-section.

Digitized by

Google

18 AUTOMOBILE-ENGINE AUXILIARIES §4

The construction of the Livingston radiator core is illustrated
in Fic^- 15- In view (a) is shown one of the strips from which

from sheet copper having a

art of each bend being oor-

All horizontal bends are left

/ wide and narrow, so that

shown in the cross-sectional

them a water space through

Bction of the arrows a. The

y side, as shown in (6), which

view clearly indicates that

the four sides of each cell

are surroimded by water.

The ends of the water spaces

are dosed by soldering, and

the whole assembly is held

together by solder.

21. Radiator Over-
floWf Drain, Connec-
tlonsy and Supports.

Practically all modem radi-
ators aie fitted with an
overflow pipe that carries
off surplus water, due either
to filling the cooling system
too full or to expansion of
the water, and also any steam formed while the engine is in
operation. The overflow-pipe location was explained in con-
nection with Fig. 10, but is shown better at a, Fig. 16, which
is a rear view of the Mayo radiator used in some Cole cars.

22. Provision for draining the radiator of all the contained
water is usually made by fitting a drain cock 6, Fig. 16, to the
bottom of the bottom tank, although in some cases, where
part of the cooling system is located at a lower level than the
bottom of the lower tank, the drain cock is applied to the
lowest point of this part. Generally, the drain cock is located
where it will surely drain the entire cooling system.

Digitized by

Google

§ 4 AUTOMOBILE-ENGINE AUXILIARIES 19

23* The top and bottom connections of the radiator to the
inetallic pipes connected to the top and the bottom of the cylin-
der water-jacket or water-jackets are always made by means
of rubber-lined and rubber-covered hose that is fastened on
by hose clips of the same form as those used with ordinary
garden hose. The hose makes a flexible connection that pre-
vents the transmitting of engine vibration to the radiator;
likewise, the hose, being flexible, prevents tmdue stresses,
such as those due to any swaying of the radiator or engine on
account of distortion of the chassis frame in running the car
over rough roads, from coming on the radiator.

24. Some radiators are supported by lugs incorporated
in their construction. These lugs usually rest on the side
members erf the frame, to which they are bolted. A fairly thick
leather pad or a soft-rubber pad is usually inserted between
the lugs and the frame to prevent vibrations from being trans-
mitted to the radiator, which action would tend to destroy
the soldered joints and thus cause the radiator to leak. Some
manufacturers do not bolt the lugs tightly to the frame, but
hold them by the pressure erf springs placed between the heads
or nuts o! the holding-down bolts and the lugs or frame, thus
forming a connection that can yield slightly if the frame is
distorted. This is done in the model T Ford car, for instance.
In many cases the radiator is set on top of a front cross-
member of the frame and is bolted thereto by bolts c, Fig. 16,
with a leather or rubber strip placed between the cross-member
and the radiator.

In most cars, the top of the radiator is prevented from sway-
ing lengthwise of the car by running a brace rod from the rear
of the top tank to the front of the dash. In Pig. 16, a bracket d
is shown attached to the rear of the top radiator tank. This
bracket forms part of the same casting containing the top
radiator inlet pipe, and is used for attaching a brace rod run-
ning to the dash. At ^ is shown the hood ledge, and at / a
socket receiving the center hinge pin of the hood, which is
usually made with three longitudinal hinges, one being in the
center of the top and one at each upper comer of the radiator.

Digitized by

Google

20 AUTOMOBILE-ENGINE AUXILIARIES § 4

25. Circulating Pumps. — ^All pumps used on auto-
mobiles for circulating the cooling water are probably of the
rotary type, as distinguished from the reciprocating, or plimger,
type. There are two general classes of rotary pimips; namely,
the centrifugal and the positive, or fixed-wlufpte-per-revolution,
class. Positive circulating pumps are either of the gear or the
sliding'Vane type.

26. In Fig. 17 are shown two views of the centrifugal
circulating pump used in the Studebaker "20*' car. View (a)

Pig. 17

is taken from the front of the car, the front cover of the casing
being taken oflf in order to show the inside of the pvmip; view (6)
is a side view, the ptimp casing being shown in section. The
pimip has a rotor a that is rigidly fastened to the driving shaft 6,
which in this case is driven through a tmiversal coupling
(not shown) from the cam-shaft of the engine. The rotor
consists of two disks a' and a", between which are six curved
vanes ai. These vanes are clearly shown in view (a), in which
view the disk a' is removed in order to show the vanes. The

Digitized by

Google

§4 AUTOMOBILE-ENGINE AUXILIARIES 21

two disks and the vanes of the rotor are cast in one piece.
The rotor is enclosed in a housing c fitted with a removable
cover d. The housing has a water inlet e connected to the bot-
tom of the radiator, and a water outlet / leading to the bottom -
of the cylinder water-jacket. The disk a" of the rotor is cut
away at the center to admit to the inside of the rotor water
that comes through the passage g connected to the inlet e.
As the driving shaft 6 is turned in the direction of the arrow A,
the rotor cairies the water around and dischai^es it from the
outlet /, provided the passage outside the ptmip is open. The
discharge of water is due to both the centrifugal action and the
peripheral velocity of the water in the ptunp. To prevent
leakage, the bearing through which the driving shaft h enters
the pimip casing c has a stuflBngbox i that is packed with fibrous ,
packing, usually a prepared hemp packing.

27. A centrifugal piunp is not positive in its action; that
is, it does not deliver a definite voltune of water per revolu-
tion tmder all conditions. Thus, if by any mishap the water
outlet is closed, the water in the pump will only be whirled
around with the rotor. The pressure will not be much greater
under this condition than when the pump is discharging at a
moderate rate; it never becomes high enough to injure any
properly constructed part. This fact has led to the almost
universal adoption of the centrifugal ptunp for circulating the
cooling water.

The quantity of water that the pump wiU discharge per
minute is in a measure proportional to the size, or resistance,
of the external passage for a given speed. The qiiantity
increases as the speed incieases.

A centrifugal pump will continue to give fair service even
after the parts are considerably worn. A loose fit between
the edges of the vanes and the casing will allow some of the
water to flow back toward the center of the pump, however,
and the eddy currents thus set up will cause a loss of eflSiciency.
By placing a disk on each side, or edge, of the vanes, so that
the vanes are between the disks and connected to them, as in
Fig. 17, the wearing surfaces are made qtiite durable. In

Digitized by

Google

22 AUTOMOBILE-ENGINE AUXILIARIES §4

cheap centrifugal pumps, the vanes project from the hub with-
out a disk on either side of them. This fonn of centrifugal
pump is the least dtirable and effident.

ihown in diagrammatic form in
extent for circulating the cooling
of ordinary spiu* gears a enclosed
outlet openings b and c opposite
each other. One gear is driven
by a shaft and transmits motion
to its mate by means of the in-
termeshing teeth. The directions
of rotation of the gears and the
divided path of the liquid are
indicated by arrows. The teeth
of the gears fit closely together so
as to prevent any flow of liquid
between them, and the ends of
the gears fit snugly against the
casing.

A pump of this type delivers
the same amoimt of liqtiid per
revolution, whether the speed and
pressure aie high or low. If a
stoppage occurs in the pipes of
a pump that is closely fitted, the
pressure between the discharge
side of the ptmip and the obstruc-
tion will increase tmtil either the
pump ceases to operate or some-
thing breaks. A gear-pump oper-
ations.

water in the Peerless car use is
I gears of the herring-bone tj^pe,
„**.w* V.XV. WX.S,,,., ^. **t,. ^^ removed from the pump casing.
The operation of the ptmip is the same as that of the gear-
pvmip described in Art. 28 ; it is much more quiet in its action,
however, as the heUcal gear-teeth slide into engagement with

Digitized by

Google

§4 AUTOMOBILE-ENGINE AUXILIARIES 23

each other instead of roUing into engagement. To prevent
breakage of any important part of the power plant that may be
caused by a stoppage on the discharge side of the pump, the
manufacturers of the Peerless car provide a safety coupling
on the driving shaft of the pump, making this coupling so weak
that it will break and thereby stop the ptmip before any more
serious damage is done. Obviously, the car should not be
operated when this safety coup-
ling is broken.

30. On a number of cars,
among which may be mentioned
the Haynes and the Apperson
automobiles, a so-called sllding-
vane pump is employed for
circulating the cooling water. A
pump of this kind is shown in
Fig. 20 (a). It is composed of a
casing a, a piston 6, and two
vanes, or wings, c and c' with
springs d between them. The
piston 6 is rotated by a shaft e,
shown dotted, which is usually
driven from either the engine
cam-shaft or the magneto shaft;
the piston b is concentric with pig. 19

the shaft e. The piston and the shaft are motmted eccen-
trically in a circular machined chamber of the pump casing, as
shown. The water coming from the radiator flows to the
pump through a pipe connected at / and leaves through a pipe
connected at g, which pipe, in turn, communicates with the
bottom of the cylinder water-jacket or water-jackets. An
inlet port h and an outlet port i are cut through the wall of
the circular chamber of the casing. The two vanes c and c'
are flat and free to slide in a slot machined directly across the
piston; they are shown in perspective at {e). The one wing
has driven in it two pins that enter corresponding holes in the
second wing; when the two wings are assembled in the piston.

Digitized by

Google

AUTOMOBILE-ENGINE AUXILIARIES

§4

each pin is surrounded by a spring, shown at d, view (a). A
perspective view of the piston is shown at (d), in which view
the slot previously mentioned can be clearly seen. A perspec-
tive view of the casing is shown at (6), and of the cover that
closes the casing at (c). The lowest part of the casing is fitted
with a drain cock.

The action of the pump depends on the motion of the vanes
or wings, in the circular chamber of the casing. Suppose that
the piston 6 is in the position shown in view (a) and that it
starts to rotate in the direction of the arrow /. As soon as the
vane c has covered the lower edge of the intake port A, it diives

(e)

(00

Pig. 20

the water in the crescent-shaped space between the piston b
and casing a before it and out through the outlet port i. In
the meantime, as soon as the vane c has covered the lower edge
of the inlet port h, water is diawn through the port into the
space behind the vane c until it has nearly reached the posi-
tion of the vane c\ As soon as the vane c' passes the lower edge
of the port h, it drives water before it and draws in water behind
it; the two blades thus alternate in driving the water before
them, thereby producing an almost continuous flow of water,

31. Antifreezing Mixtures for Cooling System. — If

a car is to be used in very cold weather, it is advisable to fill
the cooling system with some liquid that will not readily freeze.

Digitized by

Google

§4

AUTOMOBILE-ENGINE AUXILIARIES

In weather not colder than l(f F. above zero, especially if a
wind is blowing, it requires only a short time for watei to
freeze in the radiator if the engine is stopped out of doors.
The freezing may be prevented for a considerable time, how-
ever, by covering the radiator with a blanket or a robe.

Various substances may be mixed with water in order to
lower its freezing point; those most commonly used are wood
alcohol, denatured alcohol, calcitmi chloride, and glycerine.
Grain alcohol that is not denatured may also be used, the only
objection to it being its very high price. In emergencies,
when none of the substances just named are obtainable,
whisky, brandy, rum, gin, or any other equivalent Uquid very
rich in alcohol may be added to the cooling water.

TABLE I
FREEZING POINT OF MIXTURES OF WOOD ALCOHOL AND WATER

Percentage of

Freezing Point of Mixture

Alcohol

Water

Degrees F.

18 above zero

5 above zero

2 below zero

9 below zero

15 below zero

35 below zero

32. Table I gives the approximate freezing temperatures
for various proportions of alcohol and water. Alcohol vapor-
izes and passes out of the cooling system more rapidly than does
water. It is therefore necessary in order to maintain the
proper proportions to add more alcohol than fresh water. The
vapor of the alcohol is inflammable. Care should therefore
be taken not to bring a naked light near the filler opening of
the radiator when the filler cap has been removed. None of
the alcohol solutions will injure rubber 01 attack the different
metals in the cooling system.

33« Calciimi chloride {not chloride of lime) dissolved in
water fonns a solution that will not freeze so rapidly as water

Digitized by

Google

26 AUTOMOBILE-ENGINE AUXILIARIES §4

e. Only chemically ptire calcium chloride should be used,
3ver. The impurities in ordinary commercial caldtun
ride are apt to attack some of the metals or alloys of the
ng system, especially zinc and solder. Table II gives the
x)ximate freezing points of various proportions of calcium
ride and water.

rfore using a calcium-chloride solution it is advisable to
e a test for acidity. This may be done by placing a strip
lue litmus paper, which can be bought at any drug store,
a sample of the solution. If this litmus paper turns red,

TABLE n

SZINO POINT OF HIXTUBES OF CALCIUM CHLOBIDB AND
WATER

alciiim Chloride per Gallon,
231 Cubic Inches, of Water
Potmds

Freezing Point
Degrees F.

I.O

27.0 above zero

2.0

18.0 above zero

1,5 above zero

3.5

8.0 below zero

4.0

17.0 below zero

5.0

30.0 below zero

solution is acid and mtist not be used without first neutral-
ly it. Neutralizing is done by adding slaked lime, a little
L time, imtil a strip of blue litmus paper remains blue,
iimi-chloride solutions are used very little at present.

34. Glycerine and water also form a mixttu-e that stays
liquid at a lower temperature than water alone. The glycer-
ine, however, attacks and destroys the rubber in hose connec-
tions, etc. Instead of using a mixture of just these two liquids,
alcohol is often added. The glycerine is liable to deposit on
the walls of the cooling system if the cooling mixttu-e becomes
very hot. Table III gives the approximate freezing points
of various mixtiu*es of this kind.

Digitized by

Google

§4

AUTOMOBILE-ENGINE AUXILIARIES

35. Draining tbe Cooling System. — If water alone is
used for cooling during cold weather, it should be drained off
completely when the car is left standing in a cold place over-
night. No water should be allowed to remain in any pocket
from which the water cannot drain as the radiator empties.
Although nearly all modem cooling systems will drain per-
fectly by gravity upon opening a drain cock located at the low-
est point of the system, many of the older cooling systems will
not. Some of these S5rstems cannot be emptied perfectly
except by applying air pressure to the highest point. If avail-
able, compiessed air from a storage tank should be used for

TABLE in

FRBBZ^O POINT OF MIXTURES OF GLYCERINE,
ALCOHOL, AND WATER

WOOD

Percenta|;e of
Glycerine

Percentage of
Wood Alcohol

Percentage of
Water

Freezing Point
Degrees F.

5.0

25 above zero

1 0.0

lO.O

15 above zero

12.5

8 above zero

15.0

5 below zero

12.0

25.0

10 below zero

20.0

23 below zero

this purpose; otherwise, blowing into the system with the
mouth or using a tire air pump will do.

AIR COOLING

36. In order that a cylinder may be cooled sufficiently
with air to keep the temperattu-e down to a working limit,
it is necessary to provide a greater radiating surface with which
the air can come into contact than is presented to the atmos-
phere by a cylinder having a smooth exterior. The increased
radiating surface is secured by placing projections on the parts
of the cylinder that need the most cooling. These projections
are usually in the form of fins, and may be either thin, flat

222B>-17

Digitized by

Google

28 AUTOMOBILE-ENGINE AUXILIARIES §4

rings at right angles to the cylinder, or thin, flat strips placed
radially and running lengthwise of the cylinder. In either case,
the inner edge of the fins forms an integral or a substantially
integral part of the cylinder casting. Other methods of form-
ing an increased radiating surface, such as using radial pins
either cast integral with the cylinder or substantially attached
thereto, were formerly employed, but they have become obso-
lete so far as pleasure automobiles are concerned.

Under normal conditions of operation, the air-cooled engine
runs much hotter than one cooled by water or some other
liqtiid. It is not unusual for an air-cooled engine to become
hot enough at the cylinder head and exhaust port to glow in
the dark. Engines of this class have operated successfully
for long periods at this high temperature. However, unless
the fuel supply can be completely cut off, difficulty is some-
times met in stopping engines when they are so hot.

37. There are three methods of bringing air into contact
with the radiating surfaces of the cylinders. In the first
method, the passage of the car through the air is relied on;
in the second method, air is blown against the radiating sur-
faces by a rotating fan; and in the third method, the parts
with which the air is to be brought into contact are enclosed
in a casing and a current of air is either forced through or
drawn through the casing by means of a fan. A greater amount
of air can be brought into contact with the radiating surfaces
in this manner than when they are not enclosed by a casing.

The air-cooling method first mentioned is used in the Duryea
car. The second method has been used in the Cameron car,
in some models of the Franklin cars, and in a number of other
now obsolete pleasure cars. The method in which air is forced
by a fan or a blower through a casing sunoimding the cylinders
has been used on the Frayer-Miller cars.

38. In the Franklin air-cooled automobiles, there is em-
ployed the variation of the third method mentioned in Art. 37
in which air is drawn through a casing surrounding the cylin-
ders. This system, as carried out in the Franklin six-cylinder
cars, is illustrated in Fig. 21, where some of the parts of the

Digitized by

Google

§ 4 AUTOMOBILE-ENGINE AUXILIARIES 29

car are cut away in order to show the cooling system more
clearly. Each cylinder of the engine has vertical thin metal
fins, or flanges, that are cast in the cylinder walls; also, each
engine cylinder is surroimded by a short cylindrical sheet-
metal air jacket a that is open at the top and the bottom.
These air jackets are set through a horizontal metal deck b
that touches the front of the dashboard c and is touched by
a ledge on the sides of the hood d. A vertical sheet-metal
shield e reaches from the front of the horizontal deck 6 down-

PlG.21

wards to the front cover of the engine boot, or sod pan, /, which
is open at the rear. The space under the hood is thus divided
into two compartments by the horizontal deck b and the ver-
tical shield e; the upper compartment is in communication
with the outer air through a large grilled opening d' in the
front of the hood, the griUe-work being formed from flat strips
of metal. The flywheel g of the engine is a suction fan. It
draws air through the opening in the front of the hood into the
upper air compartment and thence down through the air jackets

Digitized by

Google

30 AUTOMOBILE-ENGINE AUXILIARIES § 4

of the cylinders into the lower compartment, discharging the
air through the rear end of the sod pan /. The air in passing
over the cooling flanges of the cylinder walls cools these walls
by absorbing heat and carrying it away, the course of the air
being clearly shown by the arrows in the illustration.

EXHAUST MUFFLERS

PURPOSE OF MUFFLING

39. Gases exhausting Unrestricted from the cylinder of
an internal-combustion engine pass into the atmosphere at
a high velocity, so high, especially at high engine speeds, that
the result is a continuous noise that can be likened to a series
of sharp detonations. This noisy exhausting of the gases is
decidedly objectionable, and for this reason many efforts have
been made by inventors to produce a device that will muffle
the detonations to a degree that will render them unobjection-
able. The device used for this purpose is called an exhaust
muffler.

Generally, the exhaust may be muffled by leading the exhaust
gases into a chamber, or chambers, where they can expand
to a low pressure and cool at the same time. In most mufflers,
the single large stream of exhaust gases coming from each
cylinder is broken up into numerous small streams, or thin
sheets, to insure rapid cooling and reduction in velocity. In
some mufflers, the cooled exhaust gases are discharged into the
atmosphere in a series of fine streams, and in others, especially
the most modem mufflers, the discharge is in a single stream.
It is common practice either to place a valve of some suitable
form between the muffler and the engine, or to incorporate
a valve directly with the muffler, the valve being operated by
a conveniently located foot-pedal. This valve, known as the
muffler cut-out, opens directly to the atmosphere, and when
open, it allows the engine to exhaust directly into the air,
either for testing the regularity of the explosions or to gain a

Digitized by

Google

§ 4 AUTOMOBILE-ENGINE AUXILIARIES 31

sUght increase of power by eliminating the back pressure created
by the mtiflfler.

A good muflBier, in eff ectivdy muflBing the sound of the esca-
ping exhaust gases, will not create an excessive back pressure
on the engine.

CONSTBUCnON OP MUFFLERS

40. Fig. 22 illustrates in section a typical modem exhaust
muflBer of the type that breaks up the exhaust gases into ntuner-
ous fine streams. It has two cast-iron heads a and 6, and
four concentric cylindrical shells c, d, e, and / that are held
in position by grooves in the two heads. The assembly is
held together by long bolts that pass through both heads.
The exhatist pipe g is attached to the head a and discharges
into the inside of the shell c. The gases pass through small
perforations at the left end of the shell c into the larger shell d,
expanding in doing so, because the volume of the shell d is
much larger than that of the shell c. The gases in the shell d

Fig. 22

pass through perforations at the right end of this shell and
expand into the shell e. Then they pass through holes in the
left end of the shell e into the outer shell /, expanding therein
and, finally, they escape into the atmosphere through the
nozzle h. This type of muffler has a cut-out valve i fitted into
the head 6. This valve is opened by pulling on a cable attached
to the cut-out lever /, when the exhaust gases can pass from
the exhaust pipe g through the inside shell c and the openings
in the valve seat of i into the atmosphere.

41. The muffler used in many Stevens-Duryea cars belongs
to the type that breaks the solid stream of exhaust gases into
thin sheets; it is shown disassembled in Fig. 23. It has an

Digitized by

Google

AUTOMOBILE-ENGINE AUXILIARIES

§4

outer shell a that is closed, when assembled, by the heads b
and c. The head b is fitted with a cut-out valve J, and to this
head is connected the exhaust pipe. Placed inside of the shell a

Pig. 23

is a'series of cones e and /. The cones e aie closed at the apex
and the cones / have the apex open; that is, they are really
frustums of cones. These sheet-metal cones are held in place
by three supporting shafts g and tubular distance pieces h.
The exhaust gases on entering the mufHer strike the first closed
cone e and pass over its inside surface up to its edge; they then
pass over the outside surface into the cone /, which delivers
the gases into the inside of the second closed cone e; and so
on. The gases finally escape through a passage in the head c
into a tube and thence into the atmosphere.

42. Fig. 24 illtistrates, in longitudinal and in cross-section,
a muflBer of the type that breaks the exhaust gases into numer-
ous small streams. In this form of muffler there are six cylin-
drical steel shells, three of which are placed eccentric to the

Fig. 24

center of the muffler. The exhaust gases enter the central
chamber a of the muffler, and pass through perfoiations at
the top to the first expansion chamber formed by the anntilar

Digitized by

Google

§4 AUTOMOBILE-ENGINE AUXILIARIES 33

space between the first and second shells. The gases pass
through perforations in the bottom of the second shell into the
second expansion chamber, and leave this through perfora-
tions in the top of the third shell, entering the third expansion
chamber, and so on. The gases finally leave the mufSer through
the exhaust port b and pass into the atmosphere.

43. Mufflers are liable to fill gradually with soot (loose
carbon). For this reason, they should be taken apart occa-
sionally and cleaned. When a muffler is apart, the shells or
cones, especially those which first receive the exhaust gases,
should be examined for corrosion. If a cut-out valve is incor-
porated in the muffler, it also should be cleaned and examined,
and, if necessary, repair should be made.

MUFFLER CUT-OUTS

44. Although many cars are fitted with a muffler cut-out,
there are some that are not provided with this device. To
meet the demand of owners who desire to place a muffler cut-
out on the exhaust

pipe, nimierous cut-
out devices have been
placed on the market.
Some of them can
be applied with very
little labor.

45. Fig. 25 illus-
trates a form of muf-
fler cut-out that will
open automatically if
an explosion occurs
in the muffler, thus

acting as a safety Fig. 25

valve. It consists of a T-shaped body a that is threaded
internally at b and c to fit threads cut on the exhaust pipe.
At d is formed a valve seat that is normally closed by the
valve e, which is held to its seat by a spiing /. A light wire

Digitized by

Google

34 AUTOMOBILE-ENGINE AUXILIARIES §4

cable is attaxiied to the lever g. When this cable is ptilled in
the direction shown by the arrow, the valve e is pushed away
from its seat d and a direct passage to the atmosphere is pro-
vided for the exhaust gases. If at any time the pressure in the
exhaust pipe is great enough to overcome the tension of the
spring/, the valve e will automatically open outwards.

Fig. 26

46, The form of muffler cut-out illustrated in Fig. 26 is
intended to be clamped to the exhaust pipe after cutting a
V-shaped notch into this pipe. For this purpose the body a
is made in halves. The cut-out valve 6, which is a butterfly
valve, is fastened to a shaft c. This shaft also carries a crank d
that serves to turn the valve 6, which is shown in its open
position.

GOVERNING DEVICES

GOVERNING BY HAND OB FOOT

47, Most automobile engines are controlled by manipu-
lation of the throttle valve and the position of the spark. More
accurately, the control proper is accomplished by regulation
of the throttle, and the spark advance is regulated to keep the
ignition at its most advantageous point for developing the
maximum power of the charges received.

Digitized by

Google

§ 4 AUTOMOBILE-ENGINE AUXILIARIES 35

The maniptilation of the spark alone is sometimes, but
wrongfully, employed to modify the speed of the engine,
because, with the spark retarded to cause ignition to occur
later than it should, the power of the engine is very mate-
rially reduced. This, is a most objectionable practice for sev-
eral reasons: In the first place, it evidently wastes gasoline,
because the same result as r^ards power may be obtained
with smaller charges and an earlier spark. Second, the inflam-
mation is so prolonged that it probably is not completed at
the time the exhaust valves open, so that the valve seats are
exposed to streams of gas still btuiiing. This not only over-
heats the valves and is liable to warp them, but it soon bums
and cuts their ground faces and their seats. Third, the engine
is overheated, and preignition of the incoming charge may
result, producing explosions in the carbureter and intake pipe.
It is, however, pennissible to retard the spark to prevent racing,
that is, running too fast, when the throttle is nearly closed and
the engine is running light, with the car standing still.

48. Inasmuch as automobile engines are operated under
wide variations of speed and load, it follows that for correct
action the throttle and the spark cannot always be operated
together. For example, a rarefied charge, such as is obtained
with the engine running at meditmi speed, with the throttle
nearly closed, will bum in a comparatively slow manner and
requires an advanced spark for its prompt combustion. Sup-
pose, now, that the car is running at moderate speed tmder these
conditions, as it may when descending a slight grade, or even
on level ground. If a slight up-grade is encountered, the oper-
ator will open the throttle to increase the power. Under such
conditions the speed of the engine will probably not increase,
but it will be found that the spark advance suitable for the pre-
vious conditions is too early for the increased charges. This
will be indicated by the laboring soimd and possible pounding
of the engine, either of which sounds may be stopped at once
by slightly retarding the spark.

49. The manipulation of the throttle valve is eflfected
either by means of a hand throttle lever carried as a general

Digitized by

Google

36 AUTOMOBILE-ENGINE AUXILIARIES § 4

rule at or near the top of the steering-gear column, or by a
foot throttle lever moiinted on the foot-board. Where cars are
fitted with hand throttle lever and foot throttle lever, they are
usually so connected that either can operate upon the throttle
valve. The foot throttle lever, which is commonly called the
accelerator y is connected by a spring in such a maimer as to
tend always to close the throttle valve when not pressed by
the foot. The hand throttle lever will stay in any position
in which it may be placed on its quadrant; the accelerator,
however, must be held with the foot if it is used in driving the
car. In some cars the accelerator, instead of being depressed
to open the throttle, is moved sidewise or forward with the
foot; in a few cars the hand throttle lever and the accelerator
are positively connected, so that both always move together.

50. The principle involved in connecting the hand, and,
foot throttle levers so that either can operate the throttle valve

Fig. 27

is illustrated in Fig. 27. There are two crank-arms a and 6
that are independent of each other; both are mounted, and free
to turn on, the same stud c, which is rigidly fixed in position.
The lever b has a boss 6' raised so as to form a stop against which
the lever a may rest.. The rod d is hinged to the lever a and
connects with the hand throttle lever; the rod e is connected
to the accelerator, and the rod / to the carbureter throttle
valve. The rods e and / are hinged to the lever h. A helical
spring g is hooked to the lever b at one end and to some

Digitized by

Google

§4 AUTOMOBILE-ENGINE AUXILIARIES 37

stationary part of the car at the other end. This spring g is
always so mounted that it tends to pull the rod/ in the right
direction to close the throttle valve.

Suppose that the hand throttle lever is operated so as to
push the rod d in the direction of the arrow h. This move-
ment causes the lever a to swing in the direction of the arrow i,
carrjring the lever b with it in the same direction and causing
the rod / to move in the direction of the arrow ; , thereby open-
ing the throttle valve. When the hpid throttle lever is oper-
ated in an opposite direction, the rod d and lever a are posi-
tively pulled back by that lever; the lever b and the rod / are
pulled back by the spring g, however, which tends to keep the
projection V of the lever b in contact with the lever a. It
is then evident that if the hand throttle lever is moved, the
levers a and b and the rods connected to them move also, and
since the rod e connects to the accelerator, this moves in unison
with the hand throttle lever.

Now assume that the hand throttle lever has been set so
as to partly close the throttle valve and that the accelerator is
used, moving it so that the rods e and/ are pushed in the direc-
tion of the arrow ;. The rod d and the lever a remain stationary,
but the lever b swings away from the lever a; the throttle valve
is thus opened, the hand throttle lever remaining at rest. When
the pressure on the accelerator is relieved, the spring g imme-
diately pulls the lever b and the rods e and / back, thereby
closing the throttle valve.

The details of the mechanism explained by the aid of Fig. 27
naturally vary somewhat in different cars.

AUTOMATIC GOVEBNORS

51. A governing device that automatically controls the
speed of an engine, preventing it from racing when the load
is suddenly removed, as, for instance, when the clutch is sud-
denly released without simultaneously closing the throttle
valve, is known as an automatic governor. Such devices,
while at one time in great favor, are at present retained by only
a few automobile manufacturers. Automatic governors applied

Digitized by

Google

38 AUTOMOBILE-ENGINE AUXILIARIES §4

to automobile engines are of two types, namely, hydraulic
governors and centrifugal governors.

In liydraullc governors, a closing movement of the throttle
valve is brought about by increasing the pressure on a liquid
through an increase of the engine speed.

In centrifugal governors, centrifugal force acting upon
revolving weights changes their position through an increase

Pig. 28

of the engine speed; this change of position, in turn, induces
a closing of the throttle valve, thereby slowing up the engine.

52, The governor used in the Packard car is of the hydraulic
type; it is shown in connection with the circulating pump in
Fig. 28, some parts being cut away. The position of the gov-
ernor in relation to the engine has been previously shown at t\

Digitized by

Google

§4 AUTOMOBILE-ENGINH AUXILIARIES 39

Fig. 2. The governor consists essentially of a circular cham-
ber a, Fig. 28, divided by a flexible diaphragm b made of leather
and rubber. On the one side of the diaphragm is a water
space c through which passes the cooling water taken by the
circulating ptrnip d through the connection e from the bottom
of the radiator and discharged through / into the manifold
connected to the bottom of the water-jackets. On the other
side of the diaphragm there is a plunger g having a large head;
this plunger is free to slide in the bearing h and has hinged to it
the rod i, which, in turn, is connected to the carbureter throttle
valve.

The action of the governor is as follows: if the load on the
engine is decreased, as by releasing the clutch, the increase
of engine speed at once creates a greater pressure in the water
space c. In consequence, the diaphragm moves toward the
rear of the car, which is to the right in the case of Fig. 28, thereby
moving the plunger g and rod i and thus closing the throttle
further. This movement of the diaphragm takes place only
in case the hand throttle lever has not been employed in closing
the throttle valve a sufficient amount at the instant the load
on the engine was decreased. When the engine speed decreases,
the pressure in the water space is lessened, and hence the dia-
phragm tends to move to the left, thereby opening the throttle
valve further. In closing the throttle, the movement of the
diaphragm compresses a spring surrotmding a rod leading from
the carbureter to both the hand throttle and the accelerator
control mechanism; this same spring assists the diaphragm
to move to the left when the engine speed is lessened.

63. The manner in which the hand throttle, the accelerator,
and the governor are coimected together so that any one of
them can act on the carbiu^eter throttle valve is shown in
Fig. 29.

The hand throttle lever on top of the steering post, when
moved by hand, either pushes up or pulls down the tube a
inside the steering cdumn 6. A sliding sleeve c surroimds
the steering coliunn near its base and is attached to the tube a
so as to move up or down with it. A bell-crank d having a short

Digitized by

Google

AUTOMOBILE-ENGINE AUXILIARIES

§*

and a long crank-arm is pivoted at ^ to a bracket forming part
of the steering-gear casing; its short arm is attached to a collar
carried by the sliding sleeve c. The long ann of the bell-crank d
is forked at the end, the two jaws of the fork fitting loosely
into slots cut at opposite sides of a coUar /, which is loose on
the carbureter control rod g, but is confined between two com-
pression springs h and i whose tension can be adjusted by means
of the washers, nuts, and locknuts, shown at ;. The one end
of the control rod g is hinged to the accelerator pedal jfe, which
forms a bell-crank, and is fulcrumed at / to a casting that forms
a support for the steering colimm where it passes through the
dashboard of the car. The opposite end of the control rod g

Pig. 29

is hinged to the carbureter throttle-valve crank m; the rod n
hinged to the same crank connects to the governor.

54. When the hand throttle lever is used to control the
engine speed, the operation is as follows: When rotating the
hand throttle lever to open the throttle valve, the sleeve c
slides downwards, thereby rotating the bell-crank d in the direc-
tion of the arrow o. This movement of the bell-crank carries
the control rod g with it in the same direction and hence rotates
the throttle-valve crank m so as to open the throttle valve.
The governor control rod n also moves in the same direction
as the rod g, pushing the governor diaphragm 6, Fig. 28, slightly
into the water space on one side of it. Since the accelerator
pedal is hinged to the control rod g. Fig. 29, it moves up or

Digitized by

Google

§4 AUTOMOBILE-ENGINE AUXILIARIES 41

down with any motion of the hand throttle lever, but without
in any way controlling the speed of the engine. Now suppose
that, with the hand throttle lever set so as to open the throttle
valve partly, the load is suddenly taken off the engine. The
governor at once acts, pushing the rod n in the direction of
the arrow p and rotating the throttle-valve crank m so as to
close the throttle. Since the hand throttle lever is stationary,
the bell-crank d is also stationary; the control rod g slides
through the collar / in the same direction as the rod w, com-
pressing the spring h in doing so. This movement continues
tmtil the force acting on the governor diaphragm equals the
tension of the spring h. Obviously, the accelerator pedal k
moves in imison with the control rod g whenever the governor
acts.

When the accelerator is employed to control the engine speed,
the hand throttle lever is usually set for a low engine speed and
left there. Consequently, the beU-crank d and the collar /
are now stationary. Depressing the accelerator pedal k moves
the control rod g and the throttle-valve crank w so as to open
the throttle valve, compressing the spring i in doing so; when
the accelerator pedal is released, the spring i moves the control
rod g so as to close the throttle. When all pressure is removed
from the accelerator pedal, the governor is free to act again;
while the accelerator pedal is held in position, the governor
does not act.

The action of the Packard control mechanism may be stunmed
up as follows: While the hand throttle lever is moving or
stationary, the governor is free to act; the speed at which the
governor tends to maintain the engine depends on the position
of the hand throttle lever. The accelerator permits a higher
engine speed than corresponds to the position of the hand
throttle lever, since it prevents the working of the governor
while the pedal is held in position.

55. An example of a centrifugal governor is presented in
Fig. 30, which shows two views of the governor used on the
Peerless automobile. View (a) shows the position of the
moving parts when the engine is at rest, and view (6) their

Digitized by

Google

42 AUTOMOBILE-ENGINE AUXILIARIES § 4

position when the engine is running at high speed. Inside of
the aluminum casing a are two weights b pivoted at c to the
arms d. The anns d are pinned to the shaft e by means of
the pin /. Forming part of each weight is an arm g, which is

Pig. 30

connected to a sliding collar h by means of a link i. One of
these arms with its connecting link is located on each side of
the shaft e. The sliding collar is keyed to the shaft in such a
way that it turns with the shaft but is free to slide lengthwise

Digitized by

Google

§ 4 AUTOMOBILE-ENGINE AUXILIARIES 43

on it. Partly surrounding the sliding collar h and connected
to it by means of a slip ring ;, is a yoke k. This yoke is keyed
to a shaft /, and at one end of the shaft there is pinned to it a
short lever. This lever is connected by means of a rod to the
throttle valve in the carbureter. The governor is located at
the front end of the engine and is driven from the gear-train
that drives the cam-shaft, the magneto shaft, etc.

56. When the engine is not running, the weights b and the
sliding collar h take the positions shown in Fig. 30 (a). They
are held in this position by the force of a coil spring that is
fitted to one of the throttle-connecting rods and must be com-
pressed when the throttle valve is closed by the governor.
When the engine is xui^ning, centrifugal force tends* to throw
the weights outwards to the position shown in view (6). As
the weights fly outwards, the restraining spring is compressed
and the sliding collar h is pulled along the shaft e toward the
arms d by the links i. This movement of the sliding collar
turns the shaft / by means of the yoke k, and, by suitable con-
nections, tends to close the throttle valve. As the speed of the
engine is reduced, the weights b move inwards toward the shaft e,
allowing the sliding collar to move back toward the position
shown in view (a), thus permitting the throttle valve to open.

57. The method of connecting the hand throttle, the accel-
erator, and the governor on the Peerless car, so that either can
operate the carbureter throttle valve, is illustrated in Fig. 3L
The steering coltmm a carries a sliding sleeve b that can be
moved up or down by means of the hand throttle lever on the
steering post. The tube c is free to rotate on a shaft d that is
carried by the support e and the bracket /. The support e
is fixed to a cross-member of the automobile frame and the
bracket / is bolted to the casing that encloses the lower end of
the steering column. The yoke g and the arm h are both
integral with c, forming a bell-crank that is rotated when the
sleeve b is moved up or down on the steering colimm. The
shaft d is also free to rotate and has the lever i fixed to one end
and the arm ; to the other. The accelerator k and the lever /
are rigidly connected by the short shaft m, and thus turn with

222B~18

Digitized by

Google

44 AUTOMOBILE-ENGINE AUXILIARIES § 4

the shaft w, which is surrounded by a stationary bearing not
shown, as a pivot when the pedal k is depressed. An adjustable

link n connects the levers i and /. The rod o is connected at its
forward end, which is to the right in the illustration, to the

Digitized by

Google

§4 AUTOMOBILE-ENGINE AUXILIARIES 45

carbureter throttle-valve lever in such a manner that, when
the rod is moved in the direction indicated by the arrow %, the
throttle is opened, and when it is moved in the direction indi-
cated by the arrow y, the throttle is closed.

A movement of the hand lever on the steering coltunn in
the proper direction raises the sleeve 6 and this, in turn, rotates
the tube c through the yoke g. The arm h is thus rocked in
the direction of the arrow x. This movement of the arm h
is transmitted to the rod o through the spring p and the nuts g;
hence, the rod is also moved in the direction of the arrow x
and the throttle is opened. The mechanism by means of which
the sleeve h is raised or lowered is self-locking; that is, the hand
throttle lever will remain in any position in which it is placed
until moved by the operator.

With the throttle valve partly opened by means of the hand
lever, it may be still further opened by the use of the foot-pedal,
or accelerator pedal, k. Depressing this pedal swings the lever /
about the pivot m and moves the connection n ahead in the
direction of the arrow y. The shaft d is thus turned by means
of the lever t, and the arm / is consequently rocked in the direc-
tion of the arrow x. This movement of the arm ; moves the
link r and the sleeve 5 in the direction of the arrow x. Any
movement of the sleeve 5 in this direction is transmitted to the
rod o by the nuts i\ therefore, the rod o is also moved in the
direction necessary to open the throttle. However, this move-
ment of the rod compresses the spring u and it, therefore,
returns the sleeve 5 to its original position when the accelerator k
is released. By this arrangement, the throttle may be set in
any desired position by the hand lever on the steering column,
and then if more power is wanted, it may be temporarily opened
wider by the foot-pedal, or the throttle may be opened from
its closed position by this pedal. Releasing the accelerator
returns the throttle to its original opening.

Any movement of the throttle valve by the centrifugal gov-
ernor also moves the rod o. For instance, when the engine
speeds up, the automatic action of the governor partly closes
the throttle and moves the rod o in the direction of the arrow y.
This movement is restrained by the compression of the spring p

Digitized by

Googk

46 AUTOMOBILE-ENGINfi AUXILIARIES § 4

between the nuts q and the arm h\ hence, the rod is returned
to its original position when the engine again slows down.
When the centrifugal governor acts to open the throttle partly,
the spring u is compressed and it is this spring that restrains
the action of the governor.

The pin v is integral with the rod o and serves as a guide for
the sleeve s, which slides on the rod.

Briefly stated, the governor controls the speed of the engine
for any throttle opening fixed by the position of the hand
throttle lever. Depressing the accelerator pedal opens the
throttle valve and holds it open against the action of the gov-
ernor; hence, the speed of the engine for any opening of the
throttle less than the maximum opening, may be increased by
operating this pedal.

Digitized by

Google

ELECTRIC IGNITION

(PART 1)

THEORT AND APPLICATION

ELBMBNTABY PRINCIPIiBS

DEFINITIONS OF BLECTRICAIi TERMS

!• Blectrlclty is the name given to the cause of all
electric phenomena. The exact nature of electricity is not
known; but its effects, the laws governing its action, and the
methods of controlling and using it are well understood. Elec-
tricity is neither a form of matter, as matter is generally under-
stood, nor is it a form of energy, although energy is required
to move it, and when in motion it is capable of doing work.

2. Electricity may manifest its presence or movements
in various ways. For example, it may cause attractions or
repidsions of some kinds of matter; it may decompose into
elements some kinds of matter through which it passes, as
the decomposition of water into two gases, hydrogen and
oxygen; it may cause a magnetic needle to deflect; it may
cause physiological effects in or shocks to the nervous sys-
tems of all animals; it may heat substances through which
it passes; or it may pass through air in the form of an electric
spark, or arc.

3, Electricity may appear either to reside on the surface
of bodies as a cliargre, or to flow through the substance or

eorrmoHTSD sr intbrnational tkxtbook oompant. bntkrbd at •tationkim' haix. London

§6

Digitized by

Google

ELECTRIC IGNITION § 6

surface of a body as a current. That branch of the
which treats of charges on the surface of bodies is
electrostatics, and the charges are said to be electro-

)r simply static, charges of electricity. Electrodynamics

branch of science which treats of the action of electric

Electrostatics. — For present purposes, very little
>e said about electrostatics. The electricity used
iting the combustible mixture, or charge, in auto-
engines is in motion, and hence its discussion falls
lly under electrodynamics.

Conductors and Insulators. — All bodies
t electricity to some extent, and there is no known
ice that does not offer some resistance to its flow,
lies have been divided into two classes: non-con-
ps, or Insulators, which offer a very high resistance
\ passage of electricity; and conductors, which
. comparatively low resistance to the passage of
ity.

[letals and alloys allow electric current to pass through
eadily, but some offer much greater resistance to the
the current than do others. Some of the non-metallic
ices also allow the current to pass quite freely, but
luch greater resistance than do the metals. A sub-
that allows current to pass freely is called a good
or of electricity and its conductivity is said to be high.
assification of substances as conductors depends to
xtent on the nature of the service for which they are
sed.

Litomobile practice, the following substances are used
ductors: Copper in wires, switches, and parts of
tus; brass and bronze in parts of apparatus and
ery ; iron and steel as parts of the machinery ; aluminum
1 machine parts; tin-foil in connection with induction
latinum or an alloy of platinum and iridium (platino-
) for the points at which the electric spark occurs in

Digitized by

Google

§ 6 ELECTRIC IGNITION 3

igniters; and the metals, carbon, and alloys, and also solutions,
in batteries.

6. Copper is a far better conductor than any other of the
substances mentioned. Pure alumintim has about 63 per
cent, of the conductivity of copper, but the aluminima alloys
used probably seldom have more than one-eighth of the
conductivity of copper when dimensions, and not weights,
are compared. The softer irons and soft, or mild, steels
do not have more than about one-eighth of the conductivity
of copper. The hard steels have much less. The brasses
and bronzes probably never exceed one-third of the conduc-
tivity of copper.

Moist earth is a sufficiently good conductor of electricity
to cause trouble when it collects as damp dust arotmd parts
between which the current should not pass.

7. An instdatlnfiT substance is one that does not
allow any appreciable quantity of electricity to pass through
it under the condition in which it is used. The insulating
materials commonly used for the electrical parts of an auto-
mobile are: India-rubber composition; silk, and cotton on
wires, used in apparatus and for connecting them; paraffin
in induction coils and to some extent on wires; hard, or
vulcanized, rubber in induction coils, magnetos, etc.; wood
fiber (vulcanized or compressed into hard sheets, tubes, etc.)
in the electric apparatus and around wires; mica, porcelain,
and steatite, also called soapstone, in the spark plug; shellac
applied as a varnish on wood and in some parts of the appara-
tus; dry wood, varnished; paper, varnished, in induction
coils; pitch in dry batteries, and sometimes on wire.

Enamel, glass, slate, and marble are good insulators,
but they are not much used on automobiles. Dry air is
an excellent insulator. Oils are also good insulators, but
they are not intentionally used as such on automobiles.
The timer or conamutator, which forms a part of the electrical
circuit, is usually filled with grease or oil. Neither grease
nor oil could be used for lubricating purposes in such a way if
they were good conductors.

Digitized by

Google

ELECTRIC IGNITION § 6

slstance. — The opposition that a substance
he passage of a direct current through it is called
i.nce. If the sectional area of a piece of a given
5 uniform, its resistance is directly proportional to

Hence, a piece of copper wire of uniform diameter
et long has twice the resistance of 5 feet of the
; also a piece 15 feet long has three times the resist-
eet of the same wire.

engths of two pieces made of similar material are
ir resistances are inversely proportional to their
ireas. The greater the sectional area, the less the

Thus, the resistance of 1,000 feet of No. 13
re, which has a section^ area of .004067 square
999 ohms; whereas, the resistance of 1,000 feet of
pper wire, which has a sectional area of .008154
;h, or a trifle over twice the sectional area of the
re, is .9972 ohm, or very nearly half that of
J wire. Annealed, soft-copper wire instdated with
k, rubber, or composition of some kind, is about
ire used in the electrical circuits of automobiles.

ELECTROBTI^AMICS

ictplc Potential. — The electric potential of a

s electrical condition, and is analogous to pressure
head in liquids, and temperature in heat. If the
each of two connected vessels have the same head,
)e no flow from one to the other; but if the liquid in
vessels has a higher head than that in the other,
be a flow corresponding to the difference of the
milarly, if two connected bodies have the same
lotential, there will be no flow of electricity from one
3r; but if one has a higher potential than the other
f there is a difference of electrical potential — electric-
to flow from the body having the higher potential to
laving the lower potential, and the rate of flow is
al to the difference of potential.

Digitized by

Google

S 6 ELECTRIC IGNITION 5

10. The earth may be regarded as a reservoir of elec-
tricity of infinite quantity, and its potential, or pressure, may
therefore be taken as zero. For. convenience, it has been
arbitrarily assumed that the electrical condition called positive
is at a higher potential, or pressure, than the earth, while
that called negative is at a lower potential, or pressure, than
the earth; and that electricity tends to flow from a positively
to a negatively electrified body. Therefore, when a posi-
tively electrified body is connected by a conductor to the
earth, electricity is said to flow from the body to the earth;
and, conversely, when a negatively electrified body is con-
nected to the earth, electricity is said to flow from the earth
to the body. Also, when a positively and a negatively
electrified body are connected by a conductor, electricity is
said to flow from the positively electrified body to the body
having the negative charge. While these asstunptions may
or may not be true, they assist very materially in explaining
and understanding the subject of electricity.

11. Electricity is a condition of matter, and not matter
itself, as it has neither weight nor dimensions. Consequently,
the statement that electricity is flowing through a conductor
must not be taken too literally; it is only another way of say-
ing that a change, the nattire of which is not fully understood,
is taking place in the electrical condition of the conductor
and that differences of potential are tending to become equal-
ized. It must not, therefore, be supposed that any substance,
such as a liquid, is actually passing through the conductor
in the same sense that water flows through a pipe.

12. Electromotive Force. — ^The expression electro-
motive force, usually abbreviated to E. M. F., has

practically the same meaning as difference of electric poten-
tial, or electric pressure. Electromotive force is the force
that moves or tends to move electricity from one place to
another. The practical unit of electromotive force is the
volt. An instrument used to measure electric pressure and
indicate its intensity in volts is called a voltmeter.

Digitized by

Google

ELECTRIC IGNITION § 6

An electromotive force may be produced or gener-
a number of ways, among which are the following:
ly friction and electrostatic induction,
ly dipping the ends of two strips of dissimilar mate-

0 a liquid that has a greater tendency to act chemic-
one material than on the other. The electromotive
due to chemical action or affinity between the strips
liqtiid.
y magnetic induction. The explanation of this

will be made after the subject of magnetism has
Qsidered.

ly the contact of two dissimilar materials, as shown
1, when the junction d is at a different temperature

from the two ends a and 6,

pgr I Jroft I which are supposed to be at

** * the same , temperature. An

^°* ^ electromotive force produced

manner is called a thermoelectromotive force,
production of an electromotive force by friction is
vident by the charges of electricity accumulated on
oving belts. The production of electromotive forces
first and fourth methods is not of great importance
iiscussion, and will not be referred to again.

Ainx>ere9 Volt, and Olun. — ^The chemical action
ivanic cell produces an electromotive force, and this,
, causes a difference of electric pressure, or tension,

terminals of the cell. This difference of electric
5, or potential, commonly called pressure, causes a

to flow when the external circuit is closed. Both the

1 circuit and the internal circtiit offer resistance to
,w of the current. The forcing of the current through

the wire of the external circmt produces heat in the wire.
If the terminals of a dry battery are connected by a thin,
insulated magnet wire wotmd in a coil, as by winding the
wire on a spool, such as is used for silk thread, the coil will
become decidedly warm in a short time. There would be
as much heat developed in the wire if it were not coiled, but

VAAV/ AAV/T

Digitized by

Google

§6 ELECTRIC IGNITION 7

it would keep cooler on account of being more exposed to the
atmosphere.

Electric pressure is measured in volts; current in amperes;
and the electrical resistance in oliins. A pressure of 1 volt
will send a current of 1 ampere through a resistance of 1 ohm;
also 2 volts will send 2 amperes through the same resistance.

An instnmient that indicates the ntmiber of amperes of
current flowing in a circuit in which it is connected is called
an ammeter. For use in automobile practice, an ammeter
and a voltmeter are frequently combined in a single small
case that is easy to handle.

15. Oliin's JjBTw. — ^The relation between the three
factors — resistance, electric pressure, and current — is
expressed by Ohm's Isrw. If the values of any two of
these factors are known, that of the third may be calculated
by the following rules:

BxLle I. — The strength, in amperes, of a direct current
flowing in a closed circuit, when the electromotive force and
the total resistance are known, is found by dividing the electro-
motive force, in voUs, by the total resistance, in ohms; that is,

electromotive force in volts

current in amperes = ;

resistance in ohms

Rule n. — The total resistance of a closed circuit, in ohms,
when the electromotive force and the direct current are known,
is found by dividing the electromotive force, in volts, by the
current, in amperes; that is,

. - electromotive force in volts

resistance m ohms =

current in amperes

BxLle m. — The total electromotive force, in volts, expended
in a closed circuit, when the direct current and the total resist-
ance are known, is found by multiplying the current, in amperes,
by the total resistance, in ohms; that is,

electromotive force in volts = current in amperes
X resistance in ohms

Digitized by

Google

8 ELECTRIC IGNITION § 6

. The following examples show the application of
5 law.

ie I determines the strength of current that will flow
conductor of a given resistance when the pressure, in
is known.

lMPLb 1. — A circuit has a resistance of 45 ohms and an available
re of 15 volts; what is the strength of the current in amperes?

UTiON. — According to rule I, the current is equal to 15 divided
which is i ampere. Ans.

lMPLb 2. — What current can be made to flow through a circuit
: a resistance of 10 ohms, if an electromotive force of 15 volts
ied?

UTION. — According to rule I, current = 15 -f- 10 = 1^^ amperes.

Ans.

. In case the electromotive force, or difference of
tial, is known, rule II must be used to calculate the
ance of the circuit that will allow a given current to
hrough it.

LMPLB 1. — The electromotive force of a circuit is 100 volts; it is
Ae to have a current of .5 ampere flowing in the circuit; what
be the resistance?

UTION. — According to rule II, the resistance is equal to 100
1 by .5, which is 200 ohms. Ans.

LMPLB 2. — Through what resistance can an electromotive force
rolts cause a current of 5 amperes to flow?

UTION. — According to rule II, the resistance = 50 -i- 5 = 10 ohms.

Ans.

• To find how much pressure it will require to force a
current through a given resistance, it will be necessary
J rule III.

lMPLB 1. — How much pressure will it take to force a current of
ip)eres through a resistance of 5 ohms?

UTION. — According to rule III, the voltage required is equal
multiplied by 5, which is 9 volts. Ans.

lMPLe 2. — What voltage is required to send a current of
peres through a resistance of 4 ohms?
Solution. — According to rule III, the difference of potential
required «= 25 X 4 = 100 volts. Ans.

Digitized by

Google

{ 6 ELECTRIC IGNITION

THE VOLTAIC CELL.

19. If two dissimilar materials, as zinc and copper or
zinc and carbon, are partly or wholly immersed in water
in which some acid has been mixed or a salt has been dis-
solved, and are connected by a conductor outside the liquid,
chemical action will occur between the two materials and the
liquid, and an electric current will flow through the liquid
and the external circuit. Such a device is known as the
voltaic, or g^alvanlc, cell, from its discoverers, Volta
and Galvani.

20. Fig. 2 shows a glass vessel A containing water, in
which a salt commercially known as sal ammoniac (chemic-
ally known as ammonium chlo-
ride, or chloride of ammonia)

has been dissolved. At C is

shown a slab of carbon, or coke,

compressed to dense form, and

at Z, a metal plate of zinc.

A copper wire is firmly attached

to the carbon slab and also

to the zinc plate, so as to be

in intimate contact with the

material. If the free ends of

the wires are brought together, Pio- 2

and are clean, so as to make good metallic contact, a current

of electricity will flow from the carbon plate through the

wires to the zinc plate, and from the zinc plate through the

liquid to the carbon plate. The arrows show the direction

of current flow when the ends of the wires are connected

together.

The liquid, no matter what its composition may be, is
called the electrolyte, and it must be such that it will
act more readily on one plate than on the other, in order to
produce a difference of potential, or electromotive force,
between them. The resistance of the two plates and the
electrolyte is called the Internal resistance of the cell.

Digitized by

Google

10 ELECTRIC IGNITION § 6

The points where the wires are attached to the plates
outside the liqtdd are the termtaals. The one at the
carbon slab is the positive terminal, or electrode,
and is indicated by the plus sign (+); and the one at the
zinc plate is the negative terminal, or electrode, and
is indicated by the minus sign (—).

21, The equalizing flow that is constantly taking place
from one plate to the other is known as a direct current
of electricity, and is one that always flows in the same direc-
tion. An alternating: current, on the other hand,
is one that changes the direction in which it flows in a con-
ductor regularly a definite nimiber of times per second.
Alternating current is not produced by chemical action, but
is generated by mechanical means.

CIRCUITS

22. An electric circuit is a path composed of a con-
ductor or of several conductors joined together, through
which an electric current flows from a given point around the
conducting path back again to its starting point. A circuit
is broken, or open, when its conducting elements are dis-
connected in such manner as to prevent the current from
flowing. A circuit is closed, or complete, when its con-
ducting elements are so connected as to allow the current to
flow. A circuit in which the conductors have come into con-
tact with the ground, or with some electric conductor leading
to the groxmd, is said to be a firi*ounded circuit, and the
contact is called an earth, or a ground. In automobile
practice, a grounded circuit is one that is completed through
the engine and frame of the car, the wire connected to the
frame or engine being called the grounded connection, even
though there is no connection whatever with the earth.

The path of the current through the wires outside of the
cell shown in Fig. 2 is the external circuit, and that
through the cell from terminal to terminal is the Internal
circuit. If any electrical apparatus is connected into

Digitized by

Google

§6 ELECTRIC IGNITION 11

the external circuit, so that the ctwrent must pass through it,
the apparatus forms a part of the external circuit. A circuit
divided into two or more branches, each branch transmitting
part of the current, is a divided circuit; the conductors
forming these branches are said to be connected in parallel^
or multiple. Each branch taken separately is called a sliant
to the other branch or branches.

23. Resistance and Toltage of a Cell. — ^The vol-
taic, or galvanic, cell itself offers internal resistance to the
flow of current through it. This resistance must be taken
into account when calculating the current, if the internal
resistance is appreciably great in proportion to the external
resistance of the circuit. The resistance of dry cells varies
greatly, but the usual form of cell, which is 2J in.X6 in.
in size, generally has a resistance not exceeding .4 ohm,
provided it is in good condition and is not too old. The
internal resistance of the cell causes the difference of potential
at its terminals to decrease as the current in the external
circtiit increases. The voltage across the battery terminals
is therefore less than when the circuit is open and the cell
idle.

The voltage of a dry primary cell with carbon and zinc
elements varies from 1.3 to 1.6 on open circuit. When the
external circuit is closed and the current is flowing, the
pressure drops. The greater the amount of current delivered
by the cell, the greater is the drop in pressure.

EXAMPLES FOR PRACTICE

1. The total resistance of a closed circuit is 23 ohms. If the
current is 1.4 amperes, what is the total electromotive force in volts?

Ans. 32.2 volts

2. A difference of potential of 11 volts exists between the terminals
of a conductor whose resistance is 20 ohms. Find the current flowing
through the conductor. Ans. .55 ampere

3. A circuit has an available pressure of 20 volts. What is its
resistance if a current of 3 amperes can flow through it?

Ans. 6} ohms

Digitized by

Google

12 ELECTRIC IGNITION § 6

MAGNETS AND MAGNETISM

NATURAL MAGNETS

24. Near the town of Magnesia, in Asia Minor, the
ancients found an ore that possessed a remarkably attractive
power for iron. This attractive power they named magnet-
Ism, and a piece of ore having this power was termed a
magrnet. The ore itself has since been named magnetite,
and in early times was found to have the pectdiar property
of swinging, when freely suspended, so that the same end
always pointed toward the north. Owing to this fact, ships
could be steered in any desired direction by its aid, because
one end of a small piece of the stone so suspended would
always point to the north. From this fact, the name lode-
stone (meaning leading stone) was given to the nattiral ore.

ARTIFICIAL. MAGNETS

25. When a bar or a needle of hardened steel is rubbed
with a piece of lodestone, it acquires magnetic properties
similar to those of the lodestone without the latter losing any
of its magnetism. Such bars are called artificial magrnets.

Artificial magnets that retain their magnetism for a long
time are called i>ermanent magnets. A piece of hardened
steel can also be more or less permanently magnetized by

rubbing it lengthwise with a pennanent magnet. The com-
mon form of permanent magnet is a bar of steel bent in the
shape of a horseshoe and then hardened and magnetized.
A piece of soft iron called an armature, or keeper, is
placed across the two free ends to prevent the magnet from
losing its magnetism.

Digitized by

Google

§ 6 ELECTRIC IGNITION 13

26. If a bar magnet is dipped into iron filings, the filings
will be attracted toward the two ends and will adhere there in
tufts, as shown in Fig. 3, while toward the center of the bar,
half way between the ends, there is no such tendency. That
part of the magnet where there is no apparent magnetic
attraction is called the neutral regrion, and the parts around
the ends where the attraction is greatest are called poles.

27. If the north pole of one magnet is brought near the
south pole of another magnet, attraction takes place; but if
two north poles or two south poles are brought together,
they repel each other. In general, like magnetic poles repel
each other and unlike poles attract each other,

28. The earth is a great magnet whose magnetic poles
coincide nearly, but not qtiite, with the true geographical
north and south poles. By the laws of attraction and reptd-
sion just given, it is seen, therefore, why a freely suspended
magnet will always point in a north-and-south direction, as
in the case of the magnetic compass, which consists of a
magnetized steel needle resting on a fine point so as to turn
freely in a horizontal plane. The north-seeking pole of a
magnetic needle or other magnet is known as a north. iK>le
though of opposite polarity to the north pole of the earth;
and the opposite end of the magnet is called a soutli pole.
If it were customary to do so, it would be more correct to
call the north-seeking pole a south pole, or to call the earth's
north pole a south pole. It is impossible to produce a magnet
with only one pole. If a long bar magnet is broken into
any niunber of parts, each part will still be a magnet and have
a north and a south pole.

29. All magnetic substances are not necessarily magnets;
nevertheless, they are capable of being attracted by a magnet.
A piece of soft iron will be attracted toward either pole of
a magnet; but when not in the vicinity of a magnet it has
no defined poles, nor will it attract another piece of immag-
netized iron.

222B— 19

Digitized by

Google

14 ELECTRIC IGNITION § 6

30. Magnetic Lilnes of Force. — If a sheet of paper is
laid over a bar magnet, and fine iron filings are sprinkled on
the paper, the filings will arrange themselves in ciirved lines
extending from the north to the south pole, as shown in
Fig. 4, in which N S is the bar magnet. If the magnet is
placed in a vertical position with the paper over one end,
the filings will arrange themselves in lines extending radially
in all directions from the pole A^, as shown in Fig. 5. These
invisible lines of magnetic force or simply lines of
force, acting in the directions shown, make up the mag:-
netlc field of a magnet, or the surrounding space in which

Fig. 4 p,o. 5

magnetic substances are acted on by the magnet. The lines
of force as a whole may be referred to by any of the expressions
magnetism, magnetic induction, or magnetic flux,

31. The direction of the lines of force is asstuned to
be from the north to the south pole through the air or other
surrounding medium, and from the south to the north pole
through the magnet, thus completing the magnetic circuit.
Lines of force can never intersect one another. In the
magnet the lines are crowded closely together; but, as soon
as they leave the magnet, they separate as widely as possible
at the north pole and converge again at the south pole,
as shown in Figs. 4 and 5. The magnetic density is
therefore greatest in or near the iron, and decreases as the
distance from the magnet increases.

Digitized by

Google

ELECTRIC IGNITION

32. The permanent magnets used in magneto generators
are generally U-shaped, as shown in Fig. 6. The magnetic
field is much stronger in the space between the poles than
in any other region outside of the magnet itself. The direc-
tion of the magnetic lines of force is indicated by the dotted
lines and arrowheads.

By placing an iron keeper between the poles of the magnet,
as shown in Fig. 7, the magnetic flux will be confined to the
iron keeper, which offers less resistance, or reluctance, to the

TO?-:--.!:.-—.;.-.

■%

X|^^^|,

Fio. 6

Pig. 7

magnetic flux than does the air, and few or no lines of force
will pass through the surrounding air.

33. The only useful magnetic materials are iron and
steel. The latter is, of course, made up chiefly of the element
iron. Therefore, the presence of a piece of any other material,
such as copper, brass, bronze, tin, zinc, wood, rubber, etc.,
in the magnetic field will not change the direction of the lines
of force or the intensity of the magnetic flux. It should

Digitized by

Google

16 ELECTRIC IGNITION $ 6

be remembered that commercial sheet tin is made of iron or
steel coated with tin, and that some forms of wire and rod
that appear like other metals on the surface, are iron or steel
coated with the other metal.

SliECTROMAG NETS

34. If a piece of copper wire wrapped with cotton or silk
thread is wound around a wire nail, and the ends of the
wire are connected to the cell or battery terminals, as shown
in Fig. 8, evidence that a current of electricity is flowing
through the wire will be given by the nail becoming a magnet
that will attract and hold small pieces of soft iron, such as
iron filings, or even small iron tacks. If the current is

Pio. 8

broken when a tack is hanging to the magnetized nail, the
tack will drop off because the nail then ceases to be a magnet,
or at least a magnet strong enough to hold the tack. When
the circuit is again closed, the nail will again hold the tack.
The coil of wire together with the electrically magnetized
nail form what is known as an electromagnaet. The
wire winding is called the magnetlzingr^ or excltlngr coll,
and the iron or steel (nail in this case) is the core. One
end of the nail will be a north magnetic pole and the other
end a south magnetic pole.

An electromagnet loses nearly all its magnetism as soon
as the current ceases to flow. A small amount, known as
residual magnetism, is usually retained, the amount
retained being greater in cores of steel or hard iron than
in soft ones.

Digitized by

Google

i 6 ELECTRIC IGNITION 17

35. Solenoid. — ^When a conductor is bent into a long
helix of several loops, forming a solenoid, as shown in
Fig. 9, and a current is sent through it in the direction indi-
cated by the small arrows at the ends of the conductor, the
magnetic flux will thread
through the entire solenoid,
entering at one end and
passing out at the other,
as indicated by the long
arrows. The solenoid then Pio. 9

possesses a north and a south pole, a neutral region, and all
the properties of attraction and repulsion of a magnet.

36. The i)olarity of a solenoid, when carrying a cur-
rent, that is, the direction of the lines of force that thread
through it, depends on the direction in which the conductor
is coiled and the direction of the current in the conductor.

To determine the polarity of a solenoid, knowing the
direction of the current, the following rule may be applied:

Kale. — In looking at the end of a helix, if the current circu-
lates in a clockwise direction , the end next to the observer is a
south pole; if it circulates in the other, or counter-clockwise,
direction, the end next to the observer is a north pole.

Fig. 9 illustrates the first condition mentioned in the rule.

With the position of the
observer and the direc-
tion of the current as
indicated, the end to-
ward the observer is the
south pole 5 and the
other end is the north
pole N.

37. Around a solen-
oid the Unes of force
^o. 10 make complete mag-

netic circuits, exactly the same as around a bar magnet.
Fig. 10 shows the direction of the invisible lines of force

Digitized by

Google

[C IGNITION { 6

wn, the lines enter at a, leave at 6,
rough the surrounding medium,
the solenoid, that is, the exciting
;tery B.

'omagrnet. — Fig. 11 shows the
general form and construction
of a liorseslioe eleotro-

masrnet. A soft-iron bar is
bent into a U shape, leaving
two straight sides on which the
magnetizing coils are wound.
The coils must be so woimd
that the current will flow around
the cores in opposite direc-
tions, as shown by the curved
arrows in the end view; this will
make one core a north pole A^
and the other a south pole 5.
The part of the iron bar con-
ack end is called the yoke of

^ETIC INDUCTION

induction is the production
conductor or a number of con-
between the conductors and a
ty. The strength of an induced
irtional to the quickness of the
strength of the magnetic field;
motion or the stronger the field,
ctromotive force.

method of performing a simple
:tromagnetic induction. A coil
illow a solenoid b to be readily
and d wound a few times around
ther. The magnetizing or exci-

Digitized by

Google

{ 6 ELECTRIC IGNITION 19

ting cturent for the solenoid b is supplied by the battery /
through the wires g and h. When the solenoid b is thrust into
the coil a or withdrawn from it, the needle of the compass is
deflected, showing that an electric current flows in the wire
wound around the compass. The relative motion of the elec-
tromagnet b and the coil a, one within the other, causes an
electromotive force to be induced or generated in the coil a,
and an electric current results. If the two coils remain
stationary, one within the other, and the exciting current of
the solenoid is steady, the needle is not affected; but, when-
ever either coil is moved with reference to the other, the
needle will be deflected — one way for relative movement in
one direction and the other way for movement in the other
direction.

Furthermore, if the coil b is placed inside of coil a and the
current in coil b is rapidly altered in strength, as for instance,

Pig. 12

by opening or closing the circuit containing the coil b and
battery /, a current will be induced in coil a. The current
induced in coil a will flow in one direction when the circuit
of b is closed or the strength of the current in b is rapidly
increased, and in the opposite direction in coil a when the
circuit of b is opened or the strength of the current in b is
rapidly decreased. The closing and opening of the circuit
of 6, thereby inducing a current in a first in one direction and
then in the opposite direction, is the action that takes place

Digitized by

Google

20 ELECTRIC IGNITION § 6

in practically all automobile induction coils. However, to
increase the strength of the induced current in the coil a,
the coil b is invariably filled with soft-iron wire. Since the
iron wire is more permeable than air to magnetic lines of
force, more of them are produced both inside and outside of
the solenoid b when it is filled with iron than when it is filled
with air. Although the lines of force outside the coil are
always equal in number to those inside, they are farther
apart and the outside magnetic field is therefore less intense.

The effect of inserting a magnetized piece of iron, as for
instance, a permanent bar magnet, in a coil or withdrawing
it from the coil, is the same as would be produced by putting
one coil, through which a current is flowing, within another
coil or by withdrawing it. In each case a current is induced
in the outer coil.

If the number of lines of force through the coil a, Fig. 12,
is unchanging, as when the solenoid or the magnet is held
stationary with reference to the coil, no effect is shown by
the needle; but every time a change occurs in the number of
lines of force enclosed by the coil a, an electromotive force is
induced in it, and the resulting current causes the needle to
deflect.

IGNITION APPARATUS

BATTEBTBS

DEFINITIONS AND CLASSIFICATION

41. When a number of cells are connected together,
as is customary in practice, they form an electric battery.
In commercial usage, however, the term battery is indis-
criminately applied both to a group of electrically connected
cells and to a single cell; a single cell is also known as a
battery cell,

42. In electrical diagrams, cells are represented as in
Fig. 13; M and N each represent a single cell, a. and c being

Digitized by

Google

§ 6 ELECTRIC IGNITION 21

the positive electrodes and b and d the negative electrodes.
The two cells joined together as shown constitute a battery,
a and d representing the terminals of the battery, as well as
the positive electrode of M and the negative electrode of A^,
respectively. The closed loop connecting a and d is a circuit.
The arrows indicate the direction in which the current flows.

43. The electric batteries used for ignition purposes are
of two distinct classes: primary batteries and secondary, or
storage, batteries. Secondary batteries are also known as
accumulators. The primar}'- battery will deliver electric
current as soon as its parts are assembled, but with the
storage battery, electricity
from some separate source
of supply must be stored
in it before it becomes
electrically active. The
primary batteries used on
automobiles are known as
dry batteries, because they Piq- i3

have no free body of liquid to flow and splash. Primary
batteries having a free body of liquid are called wet batteries,
the principles of which have been described in connection
with the cell shown in Fig. 2.

POULRIZATION AKD DEPOLARIZATION

44. If the circuit shown in Fig. 8 is left closed for a
considerable time and the tack then pulled off, it will be found
that the electromagnet will not hold the tack again, although
the electric circuit has remained closed all the time; or, if
the apparatus is left standing with the circuit closed and the
tack suspended from the nail, the tack may become loose
and fall off of its own accord, generally after a long time.
That this dropping may occur, the tack should be of about as
great a weight as the magnet will support when the electric
circuit is first closed. The failure of the nail to hold the
tack after the current has been flowing continuously for some

Digitized by

Google

22 ELECTRIC IGNITION § 6

time is due to a decrease in the amount of current flowing.

o^i u^^i^^i action in the cell or battery required to produce

current liberates hydrogen gas, which collects
Dbles on the carbon and prevents intimate contact
5 carbon and the electrolyte, and the cell is then
polarized. This polarization reduces the
chemical action, and consequently less current is
If the surface of the carbon is made very large
m to that of the zinc, the polarization does not
pidly, nor is it so decided as in a cell of the pro-
>wn in Fig. 2, which is about 8 inches high,
tctric circuit is broken, and the apparatus is left
open circtdt for a few minutes and then closed,
will again be sufficient to magnetize the nail so
)rt the tack. The battery thus recuperates by
itself while resting. Besides the objection to
I liquid, such a battery is not suitable for auto-
ion because of polarization.

polarization is accomplished chemically by
the carbon plate with some substance with which
drogen can combine. There are many kinds of
[ primary cells, some with solid and some with
arizers.

PRIMARY BATTERIES

t Cells. — Although serviceable for ignition
th stationary gas and gasoline engines, battery
wet type are not suitable for use on automobiles,
y are usually easily broken. Besides, they are
ind the motion of the car causes the liqtiid elec-
)e thrown out of the jar. For use on portable
soline-engine outfits, the manufacturers of the
nde wet cell make a steel, porcelain-enameled
1 be made liquid tight, but the number of cells
0 obtain the required voltage for automobile-
ion, and also the large space required, precludes
ty of using them for that purpose, even though

Digitized by

Google

§ 6 ELECTRIC IGNITION 23

such cells have a much longer life than the dry type of cell
commonly employed.

47. Dry Cells. — Fig. 14 shows a section of a dry cell
such as is used for automobile ignition. The carbon rod c
is placed in the center, and the zinc forms the enclosing cup,
or a can a. Next to the can is a lining p of absorbent paper
that is completely saturated with a Uquid electrolyte con-
sisting of sal ammoniac and zinc chloride dissolved in water,
and next to the paper is a thin layer d of white paste. The
space between the carbon rod and the lining of the cup is
filled, except at the top, with the depolar-
izer m, which is a mixture of powdered
carbon or coke and manganese dioxide.
The cell is sealed water-tight with pitch
or some similar substance, which fills the
space above the depolarizer, and is per-
manently wrapped, except over the top,
with pasteboard and paper, to prevent
metallic contact with other cells in a bat-
tery.

The positive terminal is at the center
of the top, and the negative terminal is a
binding screw attached to the top edge
of the zinc cup. The cell generally used
for automobile ignition is 2\ inches in
diameter and 6 inches long. Other dry
cells similar in general appearance . to the
one just described, but differing in some Fio. 14

of the materials employed, are also extensively used for
ignition.

Dry cells of the size just mentioned usually have, when
new and in good condition, an internal resistance of from .1
to .7 ohm and an electromotive force of 1.3 to 1.6 volts.
As a rule, the best dry cells will not remain in good condition
more than 2 or 3 years; and good results should not be expected
from cells that have been kept in stock for only 1 year.

Digitized by

Google

24 ELECTRIC IGNITION § 6

BATTERY CONNECTIONS

48. If it is desired to have more current than one cell
will give, this increased current can be obtained by connect-
ing cells together. Evidently, two cells can be connected
in two ways: Either the positive (-f ), or carbon-plate,
terminal of one cell can be connected to the negative (— ),
or zinc-plate, terminal of the other (carbon to zinc), as in
Fig. 15, which shows a series connection; or similar terminals
can be connected together, as in Fig. 16, which shows a
multiple, or parallel, connection. Both of these arrange-
ments will give more current than will a single cell under
any condition.

If the external resistance of the circtiit is greater than the
internal resistance of one cell of a battery' made up of the

Fio. 15 Pio. 16

same size and kind of cells, which is usually the case in
automobile service, then series connection will give more
current than parallel connection. In Fig. 15 and succeeding
diagrams of wiring connections, the positive, or carbon-
plate, terminal is located at the center of each cell, the nega-
tive, or zinc-plate terminal being placed at the edge of each
cell, as is customary in actual practice.

49. Series-Battery Connections. — If two or

more cells are connected in series, as in Fig. 15, the positive
terminal of one and the negative terminal of the other become
the terminals of the battery. The voltage of the battery is
measured between the battery terminals. When the circuit
is open, as shown, the voltage of the two-cell series-connected
battery is twice that of one cell, provided the cells are alike
or have the same voltage. In any case, the battery voltage
of series-connected cells on open circuit is equal to the sum
of the voitages of the two ceils. If each cell gives 1.5 volts,

Digitized by

Google

i 6 ELECTRIC IGNITION 25

then the battery of two series-connected cells will give
2 X 1.5 = 3 volts. If four cells are put in series, as in Fig. 17,
the voltage will be 4X1.5 = 6 volts. Six cells in series will
give 6X1.5 = 9 volts.

In series-connected cells, the internal resistance of the
battery is increased by the addition of cells. Thus, the
resistance of a two-cell series battery is twice that of a single
cell, provided the cells are aUke and in the same condition;
of a fotir-cell battery, four times that of a single cell; and
of a six-cell battery, six times that of one cell.

50. The total resistance of a circuit containing primary
cells is equal to the internal resistance of the battery plus
the resistance of the external circuit. The resistance of a
given external circuit remains approximately constant,
while the internal resistance varies with the number of cells

Pio. 17

constituting the battery. Hence, the total resistance does
not vary in direct proportion to the number of cells in the
battery. For instance, if the external resistance is 5 ohms
and the battery consists of six cells, each having an internal
resistance of .4 ohm, the internal resistance will be 6X.4
= 2.4 ohms, and the total resistance of the circuit will be
2.4 + 5 = 7.4 ohms. If two cells are added, the internal
resistance will be 3.2 ohms and the total resistance 8.2 ohms.
It will thus be seen that the total resistance of the circtiit
does not vary proportionally with the number of cells; in
other words, the total resistance increases less rapidly than
the number of cells. Now, it has been shown that the
electromotive force of a battery of similar cells is proportional
to the ntmiber of cells; that is, if the voltage of six cells is
6X1.3 = 7.8, the voltage of eight similar cells will be 8X1.3
= 10.4.

Digitized by

Google

26 ELECTRIC IGNITION § 6

The current flowing in a circuit containing a battery and
an external resistance is equal to the voltage of the battery
measured on open circuit divided by the total resistance of
the circuit.

Example 1. — If there are six cells, each having an open-circuit
voltage of 1.3 and an internal resistance of A ohm, what current will
flow through an external circuit of 5 ohms?

Solution. — The voltage of the battery is 6X 1.3 = 7.8; the internal
resistance, 6X.4«=»2.4 ohms; and the total resistance of the circuit,
2.4 + 5 — 7.4 ohms. Therefore, the current through the entire circuit
is 7.8 -i- 7.4 « 1.05 amperes. Ans.

Example 2. — If there are eight cells, each having an open-circuit
electromotive force of 1.3 volts and an internal resistance of .4 ohm,
connected to an external circuit of 5 ohms, what current will flow
through the circuit?

Solution. — The voltage of the battery is 8X1.3 -=10.4 and the
internal resistance, 8 X '.4 — 3.2 ohms. Therefore, the total resistance
of the circuit is 5 + 3.2«=8.2 ohms, and the current through the circuit
is 10.4 -^ 8.2 -1.27 amperes. Ans.

51. Be versed Connections In Series Battery. —

If one of the cells in a series battery is reversed, as shown

Pio. 18

in Fig. 18, the voltage on open circuit will be reduced to the
same extent as if two cells had been removed from the prop-
erly connected battery of the same number of cells. The
pressure of the reversed cell counteracts the pressure of one
of the properly connected cells. Primary cells in a series
battery are not injured by the reversal of one or more of them.

52, Multiple or Parallel Battery Connections. — If

two or more cells are connected in parallel, carbon to carbon
and zinc to zinc, the carbon side will be the positive terminal

Digitized by

Google

5 6 ELECTRIC .IGNITION 27

and the zinc side the negative terminal, as shown in Fig. 19.
The voltage, or presstire, remains the same as for one cell.
The internal resistance of the battery is reduced below
that of one cell, because there is a greater sectional area of
battery materials for the current to pass through. There-

Pio. 19

fore, the total resistance of the complete circuit, external
plus internal, is reduced by increasing the number of parallel-
connected cells. As the pressure remains unchanged, the
ratio of the pressure to the total resistance is increased, and
this means an increase of current. The internal resistance
of two similar cells in parallel is half that of one cell; of
four similar cells in parallel, one-fourth that of one cell,
and of six similar cells, one-sixth that of one cell. All
the cells of a parallel-connected battery should be of the same
make, or at least made of the same materials, and should
have the same voltage. It is best to have all of them just
alike. If cells giving different pressures are used, the action
will be similar to that described in the next article.

=^^

Pig. 20

53. Reversed Connections In Parallel Battery. — ^If

one of the cells in a parallel-coimected battery is reversed,
as shown at a, Fig. 20, the current will flow, as indicated by
the arrows, until the cells properly connected in parallel
are exhausted. The reversed cell corresponds in a way to
a closed external circuit, which, with dry cells, is of small
or low, resistance. Hence, the real external circuit will
receive practically no current.

ExAiiPLB. — If a battery consisting of two cells connected in parallel,
each cell having a voltage on open circuit of 1.3 and an internal

Digitized by

Google

2ft ELECTRIC IGNITION § 6

nee of .4 ohm, is connected to an external circuit of 6 ohms,
vill be the current in the external circuit?

UTiON. — The voltage of the battery is 1.3; the internal resistance,
= .2 ohm; and the total resistance of the circuit, .2 + 6 = 5.2 ohms,
irrent in the external circuit is therefore 1.3 -5- 5.2 = .025 ampere.

Ans.

• Parallel-Series Battery Connections. — If two

batteries of the same number of like cells are

connected in parallel, as

in Fig. 21, the pressure

will be the same as that

' of one series. Each series

of cells may be considered

as a unit and may be

I dealt with as a single cell

having a pressure and a

Fig. 21 resistance equal to that of

iries. Thus, if the series consists of four cells having a

ire of 1 . 5 volts each , the pressure of the unit will be 4 X 1 . 5

olts, and the internal resistance of the unit will be four

; that of one cell. The internal resistance of a battery of

sries sets, each set of the same number of cells, is one-half

oi one set, or unit. For three series of four cells each,

itemal resistance is one-third that of one set having

^ells in series. When there are as many series as there

jUs in each series, the internal resistance of the battery

same as that of one cell.

:h series of cells forming a unit should have the same
>er of cells; otherwise, the higher pressure of the series
g the greater number of cells will force current back
gh the series having the smaller number and exhaust
ells in the larger series. A reversed cell in a parallel-
battery has much the same bad effect as a reversed
ti a single parallel arrangement of cells, as explained
5 preceding article.

\MPLB. — A battery consists of eight ceUs connected in two
i\ rows of four cells in series in each row. Each cell has ao

Digitized by

Google

§ 6 ELECTRIC IGNITION 29

electromotive force of 1.3 volts and an internal resistance of .4 ohm.
What current will flow from this battery through an external circuit
of 5 ohms?

Solution. — The voltage of one row of four cells in series is 4 X 1.3
= 5.2. Putting cells in parallel does not increase the voltage; hence,
the voltage of two parallel rows of cells is the same as that of one
row, and in this case the voltage of the battery is 5.2. The internal
resistance of one row is .4 X .4 = 1.6 ohms; but two rows in parallel will
have one-half the resistance of one cell. Hence, the internal resistance
of the battery is 1.6 ^2 = .8 ohm. The total resistance, therefore, is
.8 + 5 = 5.8 ohms, and the current in the external circuit is
5.2 4- 5.8 = .896, or .9, ampere. Ans.

55. Increasing the number of good cells in an ignition
circuit will increase the current in the circuit, provided, of
course, that the cells are properly connected. The total
electromotive force is increased as the number of cells in
series is increased; or, the internal resistance of the battery is
decreased as the ntmiber of sets of cells in parallel is increased.
In both cases, however, the resistance of the external circuit
remains unchanged. Hence, the current is increased in the first
case because the electromotive force applied to the circuit
increases faster than the internal resistance of the battery

Pig. 22

increases the total resistance of the circuit. In the
second case, the electromotive force and external resistance
remain constant, but the internal resistance, and hence the
total resistance of the circuit, is decreased. See Arts. 49,
50, and 52.

56. Battery-Siivltcli Connections. — The switch for
connecting two series batteries to an external circuit should

222B— 20

Digitized by

Google

30 ELECTRIC IGNITION § 6

.be made and located so as to break the connections in such
a manner, when opened, as to make it impossible for any
current to flow between the different sets of cells. Exhaustion
of the battery when not in use is thus prevented. Fig. 22
shows the correct method of coimecting a switch to a battery-
consisting of two series of cells. The wires R lead to the
external circuit. When the switch is closed in the position
shown, only series A is brought into operation, and when the
switch is moved to the dotted position, only series B is put
into circuit and A becomes idle. If the switch is placed
in mid-position so that the lever touches both contacts, all
the cells are in use, A and B working in parallel.

Pio. 23

The arrangement shown in Fig. 23 is not a good way of
making the connections, even if the whole battery is always
to be cut in when current is wanted. If, in a battery con-
nected in the maxmev shown, series A happens to be in
better condition than series B, which may be taken to mean
that its pressure is higher, current will flow in the direction
indicated by the arrows when the switch is open. This flow
will continue tmtil the pressure of series A has fallen to the
same as that of series B.

SECONDART, OR STORAGE, BATTERIES

57, The activity of a grtora^e battery, accainulator,
or secondary battery depends on internal chemical
action produced by passing an electric current through it
from some external source of supply. This operation is

Digitized by

Google

§ 6 ELECTRIC IGNITION 31

called charging the battery. After the battery is charged,
it will discharge through a closed circuit nearly the same
quantity of electricity as was used to bring about the original
chemical action. The positive terminal of a storage battery
is the one by which the charging current enters and the
discharging current leaves. The majority of storage batteries
used for electric ignition may be called lead accumulators,
since lead and its oxides enter most prominently into their
construction. In some of the other types of storage batteries

Pio. 24

less used, but gaining in prominence, iron and nickel are
used instead of lead.

58. The plates, or ir^lds, of a lead accumulator are
made either of lead, or lead alloy, with pockets, grooves,
or recesses for holding the active material. They also have
heavy lugs, or shoulders, to which the terminals are attached.
In Fig. 24 (a) is shown a single plate, the minute grooves

Digitized by

Google

:tric ignition § 6

ead oxide, and in (6) is shown a com-
es assembled in a glass vessel. The
are connected together by a strip of
used for the metal of the plates, an
fis one of the terminals of the cells,
e fastened together and are provided
imilar manner. The terminal strips
te by melting, or burning, the parts
re in contact. The vessel is filled
with an electrolyte of
dilute stdphuric acid, so
as to cover the plates
completely.

59. The containing
vessel of the battery
may be either of glass
or of rubber, and where
lightness and compact-
ness are desirable, as in
batteries for automobile
ignition, this vessel is
sometimes made of or
lined with lead and may
(h) be utilized to serve as
one of the plates. In
any case, the plates
se to each other. Strips or other
terial are placed between the plates
)ming into metallic (electric) contact,
laterials thus used as plate separators
md wood.

KiKj. 1 nere are two general types, or classes, of lead accu-
midators, named from the inventors of the methods of making
the plates. These are the Plants type, in which the plates
are formed by electrochemical action that causes a deposit
of an oxide of lead on the plates, and the Faure typ©> in
which the oxide is made into the form of paste and put into

Digitized by

Google

§ 6 ELECTRIC IGNITION 33

suitable grooves, or recesses, in the sides of the plates. Lead
oxide is the active material in each case.

61. Fig. 25 (a) shows a sectional view of a small storage
battery made for automobile-engine ignition purposes. At a
is shown the side of the positive plate supported on hard-
rubber insulators 6, and in (6) is shown an enlarged end view
of the same plate before forming. When the plate has been
electrochemically formed, all the grooves are filled with
oxide of lead. The other parts of the cell in (a) are as follows:
At c is shown the positive terminal and at d the negative
terminal carrying a binding post e\ at /, the electrolyte con-
tained in a hard-lead jar ^; at A, a hardwood case; and
at i, a hard-rubber cover fitting tightly in the lead case;
at y, a sealing compound filling the space between the lead
jar and the hardwood case and also the space over the cover;
and at k, a hard-rubber tube that contains a glass valve /
and is closed by a rubber stopper m.

The cell is so. effectually closed that it can leak but little,
even if turned upside down. The solution used in a storage
cell can be made semidry either by using an absorbent or
by introducing some substance, such as a silicate of soda,
to form a jelly with the acid. There is, however, a tendency
for a semidry storage battery to dry out completely and thus
become useless. This is especially true in a warm locality.

62. The voltage of a storage cell varies from about 2.5
when fully charged to about 1.7 when completely discharged.
The pressure falls rapidly, to the extent of about -rV volt,
when the battery first begins to discharge after being ftdly
charged. When the voltage has dropped to about 1.7 per
cell, the battery should be recharged, because it retains only
a comparatively small amount of electric energy at this
pressure, and the voltage drops rapidly during discharge after
getting this low. The life of the battery is shortened by
discharging below 1.7 volts per cell.

Storage batteries for ignition purposes are generally made
up of either three cells in series, giving an average voltage

Digitized by

Google

34 ELECTRIC IGNITION § 6

during discharge of about six, or two cells in series, with an
average discharge pressure of about 4 volts. These two
pressures are adapted to meet the requirements in operating
induction coils.

The electric resistance of a storage cell such as is used for
automobile ignition is generally higher than that of a storage
cell used for the propulsion of automobiles and other vehicles,
but it is far lower than that of a dry cell as ordinarily con-
structed. If a storage cell is short-circuited, the flow of
current will be excessive and injurious to the battery. The
maximum rate at which a storage cell or battery should be
charged and discharged is generally indicated on instructions
that accompany the battery.

63. The capacity of a storage battery is generally stated
in ampere-hours. If a battery discharges continuously at
the rate of 2 amperes for 30 hours, its capacity is 2X30
= 60 ampere-hours. Such a battery will deliver 4 amperes
for 15 hours, or 1 ampere for 60 hours. The battery will
deliver a slightly greater number of ampere-hoiu*s when
discharged slowly, as in ignition use, than when the discharge
is rapid.

64. Ohar^ngr of Storage Batteries. — ^A direct cur-
rent must always be used for charging the storage battery.
In case only an alternating current is available, an alternating-
current rectifier of some kind must be used for changing it
into direct current.

When charging a battery from any soiu*ce, especially if
there is any doubt as to the direction of flow of the current,
a test should be made to make sure that the positive plates
are connected to the positive terminal of the charging circuit.
A simple way to make this test is to attach two wires to the
source of current supply and then dip their free ends into
water made sUghtly impure by the addition of a salt or an
acid. Sulphuric acid, sal ammoniac, or common salt will
serve the purpose. The ends of the wires should be kept
well apart at first and then gradually brought nearer together.

Digitized by

Google

§ 6 ELECTRIC IGNITION 35

but they shotild be allowed to touch each other until bubbles
of gas are given oflf at one of the wire ends. Bubbles may be
given off at both ends, but they will come much more rapidly
from the negative end than from the positive end. The
immersed wire end that gives off most bubbles is the one to
be connected to the negative terminal of the storage battery;
the other wire should go to the positive terminal of the storage
battery. The positive terminal of a storage battery for
automobile ignition is generally indicated by the (+) sign,
and sometimes it is painted red. The polarity of the storage-
battery terminals may also be determined in the foregoing
manner.

If the source of current supply is of considerable capacity,
so that a short circuit would be injurious, the vessel contain-
ing the water into which the wire ends are dipped should
be of glass or some other insulating material so as to avoid
short circuiting, and the supply circuit shotdd contain a fuse
having, preferably, a capacity of 5 amperes or less. If the
voltage is high, resistance should be put in series with the
submerged wires, so as to prevent injtuy in case they get
too near together.

There are several other simple methods of determining
which is the positive side of the source of the current supply.
Among these are the turning red or blue of a solution by the
passage of a current through the liqtiid. Small and convenient
sealed-glass-tube instruments depending on this action are in
use. The positive and negative sides are generally indicated
on the instrument. Some electric-pressure measuring instru-
ments can be used for the same purpose. When such instru-
ments are properly connected across the circuit, the voltage
of the circuit will be indicated; when incorrectly connected
across the circtut either no indication will be given, or a
deflection in the wrong direction will occur.

65. The battery shotdd be charged not more rapidly
than at a rate determined by its capacity in ampere-hours,
the charging current, in amperes, being equal, for an ordinary
battery, to the ampere-hour capacity divided by 8. Thus, a

Digitized by

Google

IGNITION

§6

id be charged at 7.5 amperes or
at 10 amperes. Another, and
rge at a rate not exceeding one-

e)
3. 26

sixth the ampere-hour capacity, and then maintain this rate
by gradually cutting out resistance until the voltage reaches
2.4 or 2.5 per cell, when the cells begin to gas. The charging
current should then be cut down to one-twentieth the ampere-

Digitized by

Google

{ 6 ELECTRIC IGNITION 37

hour capacity until the cells again gas freely, indicating a
ftill charge.

If the battery is charged from a direct-current, incandescent-
light circtiit, there must be used in series with the battery a
resistance sufficient to absorb the greater portion of the volt-
age of the charging circuit. For this purpose, a bank of lamps
is generally employed. As the internal resistance of the
battery is so small as to be almost negligible, it follows
that a 100-volt lamp must be used for each 100 volts
tension of the charging current, or a 110-volt lamp for a
110-volt current.

66. Wiring connections for charging storage batteries
from direct-current lighting and power circuits are shown
diagrammatically in Fig. 26. Connections to a 110-volt
lighting circuit are shown in (a). A double-pole switch a,
with fuses 6, is connected between the mains and the battery,
as shown. In series with the battery c is a number of lamps,
by means of which the charging current is limited to the
proper amount. It is advisable to connect an ammeter d in
circuit, though this is not absolutely necessary.

The number of lamps required depends on the line voltage
and on the charging rate of the cells. If the line pressure
is 100 to 120 volts and only three or four cells are to be
charged with a current of 5 amperes, then five 32-candle-
power lamps requiring 1 ampere each, connected in multiple,
as shown in (a), will be sufficient. If 16-candlepower lamps
requiring i ampere each are used, it will be necessary to
connect ten in parallel. With a 220-volt circuit, there will be
required twice as many lamps as with the 110-volt circuit, the
second set of lamps being placed in series with the first. If
the line pressure is 500 volts, it will be necessary to connect
twenty-five 32-candlepower lamps in five rows of five lamps
in series in each row, as shown in (6), or fifty 16-candlepower
lamps in ten rows, five lamps in series in each row. In case it
is convenient to charge at a lower rate, fewer rows of lamps
will be needed, but the time for charging will be proportion-
ately increased.

Digitized by

Google

38 ELECTRIC IGNITION § 6

To charge a low-voltage battery, such as an ignition
storage battery, from a 500-volt, direct-current circuit is a
very inefficient method. The high voltage makes it some-
what dangerous and requires that very good instdation be
used throughout the circtiit.

67. Lamps form a convenient resistance, as they are
easily obtained, but an adjustable rheostat is frequently used,
as shown at f, Fig. 26 (c). The amount of resistance required
in the rheostat may be calculated by subtracting the approx-
imate voltage at which the storage battery should be charged
from the charging line of voltage, and then dividing this
difference by the desired charging current.

Example. — A 6- volt ignition storage battery is to be charged
from a 110-volt circuit. How much resistance should be connected
in series with it, if the charging current is to be 4 amperes?

Solution. — ^The difference between 110 and 6 is 104 volts. There-
fore, 104-^4 = 26 ohms. Ans.

This resistance should be adjustable, so that some of it can be cut
out as the voltage of the cells increases, and it must be made of wire
large enough to carry at least 4 amperes without overheating.

Charging with resistance in series is at best a makeshift,
because it involves a large loss of energy; but in the case of
small, portable batteries, this waste is not a very serious
matter, especially as the use of the series resistance gives
the most convenient and simple means of charging from
existing circuits.

68. Becliar^iiigr of Storagre Batteries Wlien Not
In Use. — ^To keep a storage battery in good condition,
it shotdd be charged at least once a month, whether used
or not, and it shotdd preferably be kept in a cool place. Of
course, if its full capacity has not been used, not so many
ampere-hours will be reqtiired to recharge it. If the battery
is not to be used, recharging it once very 2 months may be
sufficient, provided the battery is kept in a cold place. II
shotdd not, however, be allowed to freeze.

An ordinary ignition storage battery should not be permitted
to stand without any solution in it, because in such a case

Digitized by

Google

§ 6 ELECTRIC IGNITION 39

the wooden separating pieces between the plates will rot
and the battery will have to be taken to pieces in order to
replace them when it is to be used again.

69. Ij&ying Up of Storagre Battery. — If the battery
must be laid away, say for 6 months or longer, without
recharging, proceed as follows: After thoroughly charging
the battery, remove the electrol5rte into convenient clean
bottles or other non-metallic receptacles that can be closed
tightly, so as to preserve it for future use. Then refill the
battery with fresh, pure water, allow it to stand for 12 or
15 hours, and pour off the water. The plates are then in
a condition to stand indefinitely. However, if the plates
are held apart by wooden separators, these should be removed
before drawing off the water; otherwise, they will rot. If
the separators are in good condition, they may be used again,
provided they are kept submerged in water. Generally,
it will be found better to throw them away and use new
separators when the battery is to be used again. ^

Most ignition batteries are covered with a sealing com-
pound, and to put such a battery out of use in the manner
just described, it will be necessary to remove this compound,
as well as the plates and their wooden separators, from the
case. The compound and plates may be removed, usually
together, by nmning a heated knife between the case and the
compound. Before removing the compound and plates,
it may be possible to find out from the maker of the battery
whether the separators are made of wood or of some other
material. If they are made of hard rubber or glass, their
removal is unnecessary. Any sediment in the battery
should be thoroughly washed out or otherwise removed
when the battery is put out of use. Rather than lay an
ignition storage battery away with no solution covering the
plates, it is usually preferable to give the battery a freshening
charge every month, or at least every 2 months.

Digitized by

Google

40 ELECTRIC IGNITION § 6

CURRENT CONVERSION FOR BATTERY
CHARGING

use of alternating cturent in charging

it must, as has already been mentioned,

direct cturent. Two distinct kinds of

d for obtaining direct current from an

circuit. One is of the nature of a com-
or and electric generator, called a tnotor-
er, known as a mercury-vapor converter,

moving parts, except such as are moved

en era tors. — By connecting an alter-
:tric motor to a direct-current electric
D drive the latter mechanically, a direct
5-battery charging can be obtained from
le electric pressure of the direct current
\ suitable, and an electric resistance, vari-
the operator, is usually necessar}'' in order
►tmt of current flowing through the storage
Df using two separate machines, however,
employ a motor-generator, which is a
hat appears externally much like an ordi-
ator, but is really two machines in com-
tme base.

pe of motor-generator has two armatures
one being wound for alternating current
irect current. The motor armature has a
Slip ring ciiiu uuAicutor brushes, through which the alternating
current is led to it, while the generator armature has a seg-
mental commutator and brushes, through which the direct
mrrent generated in the armature is transmitted to the
circuit containing the storage battery to be charged.

72. Rectifiers. — The operation of a mercury-vapor
rectifying apparatus for alternating current depends
on the fact that the vapor of mercury — a liquid metal much
used in thermometers — allows current to flow through it in

Digitized by

Google

§ 6 ELECTRIC IGNITION 41

one direction tinder certain conditions, but opposes its flow
in the opposite direction. Except in some designs, after the
apparatus is started, none of its parts move.

73. With some forms of alternating-current rectifiers
on the market, dependence is placed on chemical action for
rectifying the current; but as now made and used, they
appear to be inefficient and expensive to operate when
compared with mercury-vapor apparatus.

SPARK COrLS

INDUCTANCE. OR KICK, COILS

74. If a short piece of wire is connected to one of the
terminals of a dry battery, and the free end of the wire is
struck against the other terminal, a small spark will generally
appear as the contact between the wire and terminal is
broken; that is, at the instant the wire is drawn away from
the terminal. If a wire several feet long, say 15 feet of No. 28,
B. & S. (.0126 inch in diameter) copper insulated magnet
wire, not coiled, is used in the same manner, the spark will
be smaller, asstmiing that the short wire is of the same size
as, or at least not much thinner than, the long one. In order
to make the case simple, it will be asstmied that both wires
are of the same thickness. The smaller spark with the
longer wire is due to the smaller amount of current that
flows through it on account of its greater resistance. .

If the longer insulated wire is now wound around a wooden
lead pencil into as short a coil as possible, with the turns
piled on top of each other, so that there are a hundred turns
or more, a more decided spark will be produced, the longer
spark being due to coiling of the wire. The spark is stronger
when the circuit is broken quickly than when the separation
of the contact points is slow.

The current in the coil decreases, of course, from its maxi-
mum strength to zero when the connection is broken and the

Digitized by

Google

42 ELECTRIC IGNITION § 6

circuit opened. The decreasing current in each turn of the
coil acts inductively on the current in the other turns in such
a manner as to resist sudden decrease. Consequently, the
current continues for a longer time across the space between
the separated contact points, and when the points are sepa-
rated qtiickly, it also continues across a longer space or a
wider gap. The wooden lead pencil has no effect on the spark.
This action of the coil is called self-induction. Self-
induction tends to prevent a rapid change in the strength of
an electric current.

75. By substituting a piece of soft iron for the lead
pencil, the spark will be made still stronger. This is due to

the fact that the iron,
which is a magnetic sub-
stance, allows the same
current in the same coil
to produce more lines of
force through it. The
I iron resists any change in
its magnetism; hence, the
decrease of magnetism in
the iron core of the coil as
^'°' ^ the current decreases tends

to prevent a rapid decrease of current.

A change in the ctirrent in the coil induces in the iron core
electric currents that reduce the rapidity with which the
magnetism of the core diminishes, thereby reducing the
rapidity with which the current in the coil decreases. Smaller
currents are induced in a core made of a bimdle of small iron
wires than in a core that is solid. This is due to the resistance
offered by the dirt, grease, and rust on the surface of the
wires. Hence, a wire core causes less decrease in the rapidity
with which the current in the coil decreases, and consequently,
a greater spark is produced by a given coil with an iron-wire
core than one with a solid-iron core.

The reduction of the rate of increase of current when the
circuit is closed is of no importance in connection with

Digitized by

Google

§ 6 ELECTRIC IGNITION 43

ignition by the contact method, with which system of ignition
inductance coils are us^d.

76. In technical phraseology, a coil of insulated non-
magnetic wire, with a soft-iron core made up as just described
is known as an inductance coll, but in connection with
electric ignition it is variously designated as a make-and-break
coil, a primary spark coil, and a kick coil. The term spark
coil is also applied to it as well as to other types of coils used
for ignition purposes. When used in conjtmction with a
battery that gives enough current, a kick coil of sufficient
inductive strength will produce a spark hot enough to ignite
a combustible gaseous mixture. Such a coil, suitably
mounted, is shown in Fig. 27. The two screws with nurled
nuts are the terminals of the coil.

INDUCTION COIIiS

77. Suppose that to a kick coil Uke the one shown in
Fig. 27 is added another coil of insulated wire, wound around
the outside of the coil so that the two coils are concentric,
the ends of the wire of the outer coil being connected together
electrically, metal to metal. Then by connecting the wires
of a battery to the terminals of the kick coil an electric current
will be induced in and flow through the outer coil during the
time that the battery current is gaining its full strength.
As soon as the battery current gains its full strength, the
current in the outer coil will cease, and there will be no current
in it while the battery current continues to flow steadily;
but if the battery current is interrupted, current will again
be induced in the outer coil during the time that the battery
current is dropping to zero value. The current is induced
in the outer coil only dtiring the time that the current i?
changing in strength in the inner coil. Any change in the
strength of the current in the inner coil induces a current
in the outer coil. The strength of the induced current is
proportional to the rate, or rapidity, of change of current in
the inner coil.

Digitized by

Google

ELECTRIC IGNITION { 6

I through which the battery current flows is called
Apy coil; and that in which current is induced,
idapy coll. The current in the primary coil is

primary current, and the induced current in
lary coil, the secondary current.
tie primary current is increasing, the induced second-
it flows in a direction opposite to that of the primary
md while the primary current is decreasing, the

current flows in the same direction as the primary
Thus, as the primary circuit is closed and opened,
iary current flows first in one direction and then
er.

: the ends of the wires of the secondary coil are
and left apart, there will be a difference of electric
induced between them when the current in the
oil is either increasing or decreasing. The intensity
jssure is proportional to the number of turns in the

coil, or approximately so. It is also proportional,
;ure, to the number of turns in the primary coil
e rate of change of the primary current. With a
lary current, the rate of change is more rapid than
all current when the circuit is closed or opened,
lie secondary coil has a very great number of turns,
of even moderate size will supply sufficient current

a pressure high enough to cause a spark to jump
air gap between the ends of the wire of the secondary

they are a short distance apart. On account of
iifference between the pressure used to send current
tie primary coil and that induced in the secondary
Drimary is also called the lo-w-tenslon coll, and
lar>% the lii^li-tenslon coll.

79. The primary current can be stopped more abruptly
by connecting an electric condenser to opposite sides of the
point where the primary circuit is broken. The more abrupt
cessation corresponds to a more rapid rate of change in the
strength of the primary current, and consequently a higher

Digitized by

Google

§ 6 ELECTRIC IGNITION 45

tension is induced in the secondary coil. There is also less
tendency to bum, or fuse, the contact points in the primary
circuit when a condenser is attached.

80. An electric condenser, such as is used for
ignition on automobiles, is made up of a number of sheets
of tin-foil and sheets of some instdating material, such as
paraffined paper, laid together alternately, so that adjacent
sheets of the tin-foil are insulated from each other by the
paper. In Fig. 28 the lines a and b represent the edges of
the tin-foil sheets, and the heavy lines t, the edges of the
sheets of insulating material. All the alternate sheets of .
tin-foil a are connected to-
gether by a conductor, and
all the remaining tin-foil
sheets 6, by another con-
ductor. These two conduc-
tors are generally known as
the sides of the condenser.
The sheets may be ctu^ed as
well as fiat.

±L

81. A transformer, or
non-vibrator Induction- *

coll — di coil without any pro- ^°' ^

vision in itself for opening and closing the primary circtdt — ^is
frequently used in connection with a mechanically driven
electric generator to produce a jump spark in a high-tension
ignition system. The generator is provided with means of
opening and closing the circuit in such a case.

Fig. 29 shows a non-vibrator coil, or transformer, and a
condenser connected up with a battery and a switch for
closing and breaking the primary circuit. The primary
winding or coil a is surrounded by the secondary coil 6, and
within it is the magnetic core c made up of a bundle of soft-
iron wires. The battery d is in circuit with the primary coil,
and the condenser / is connected to the primary circuit on
opposite sides of the switch t.

222B— 21

Digitized by

Google

46 ELECTRIC IGNITION § 6

When the arm h of the switch rotates about g, the contact
point on it touches the terminal to which the end i of the
primary wire is attached and closes the primary circuit.
Current immediately begins to flow through the primary
coil, and the rate of current increase may be rapid enough to
induce sufficient tension between the terminals of the second-
ary coil to make a spark jump between the ends of the wire
at /. The condenser has no appreciable effect when the
circuit is closed and the current increasing, or when the cur-
rent is flowing steadily,
as the condenser is
merely short-circuited
by the closing of the
switch.

82. The switch arm,
continuing its rotation,
next separates from i
and thus breaks the
primary circuit. The
self-inductive action of
the primary coil tends
to keep the primary cur-
rent flowing after the
circuit is broken at t.
Without the condenser,
^^°- ^ an appreciable spark, or

arc, would be formed at i; but with the condenser, the energy
that wotdd be expended in forming the arc is diverted into the
condenser, and the arc is prevented from forming, or at least
from being as intense and from continuing as long as it wotdd
without the condenser. Thus, the current is stopped quicker;
that is, its rate of decrease from normal value to zero is much
greater. Hence, a greater electromotive force is induced in
the secondary coil. Furthermore, the energy received by the
condenser is given back to the primary circuit, producing a
flow of current through the primary circuit in a direction
opposite to that in which the battery sends current through it.

Digitized by

Google

§ 6 ELECTRIC IGNITION 47

This reversed current produced by the discharge of the
condenser induces in the secondary coil an electric cturent
that flows in the same direction as the current induced by
the decrease of primary current. Thus, the electromotive
force induced in the secondary winding is further increased
by this action. The difference of potential between the
terminals of the secondary coil is therefore greater when the
primary current is interrupted than when it begins.

83. The distance between the spark points of the second-
ary can be so adjusted that, while a spark will jimip between
them at the instant of breaking the primary drctut, none
will jimip at the time of closing the primary circuit.

A safety spark gap is sometimes provided at k, Fig. 29,
to prevent possible damage due to an abnormally high
pressure in the secondary coil; otherwise, if the gap between
the points / is very wide, or if an excessive ctirrent is sent
through the primary coil, breaking down of the insulation
might occur. A spark jimips across the safety gap before
the pressiu-e becomes higher than the insulation will stand.
In automobile practice, the width of the safety gap is about
i inch.

84. An induction coil that repeatedly opens and closes
the primary circtiit by its own magnetic action, in conjunction
with the elastic action of a spring, is illustrated diagram-
matically in Fig. 30. The primary exciting current is supplied
by the battery B, and the circuit may be traced as follows:
From the positive terminal of the battery through wire Lj-
binding post Pj-switch W^-post £-screw AT-contact Z>-flat
spring F-wire P-primary coil P-wire P'-binding post
Pj-wire Lj to the negative terminal of the battery. On
closing the switch W, current flows momentarily through this
circuit and magnetizes the core C, which attracts the piece of
soft iron H attached to the end of the flat spring F and breaks
the contact at D, The current then ceases to flow, core C
loses its magnetism, and the reaction of the spring closes the
contact at £>, thtis permitting the current to flow again.

Digitized by

Google

48 ELECTRIC IGNITION § 6

These operations are repeated in rapid succession, thus con-
tinually changing the magnetism in the core C, and thereby-
inducing in the secondary coil an alternating electromotive
force. The terminals of the secondary coil 5, which is woimd
over the primary coil on the spool 0, are connected to binding
posts 5i, 52, to which may be connected the external circuit
containing the spark plug.

85. A condenser R consisting of insulated plates a, ft
has its terminals connected in the usual manner to the

Pio. 30

opposite sides of the contact points where the primary
current is interrupted. The condenser discharge current,
which lasts but an instant, passes from aj through E-W-P^
-LjL-^-Lj-Pa-P'-coil P-wire P-ftj* *^^s opposing the direc-
tion in which the current was flowing in coil P before the
contact at D was opened. This discharge immediately stops
the current that was flowing in coil P, and may even start
an appreciable current in the opposite direction. The
magnetization of the core C is thus reduced almost instantly

Digitized by

Google

ELECTRIC IGNITION

to zero, and an intense electromotive force is induced in the
secondary coil.

A condenser of suitable capacity for the coil with which it
is to be used must be selected. If this is done, the spark
at the contact maker when it opens the circuit through the
primary coil is almost entirely destroyed, and the induced
electromotive force is very much increased. When the cir-
cuit through the battery and the primary coil is closed by
the contact maker, the induced electromotive force in the
secondary coil is not large; it is when the contact maker
opens the circuit that the greatest effect is produced.

It is immaterial whether the positive or the negative termi-
nal of the battery is connected to the primary terminal P
of the coil.

The part HDF is
called the vibrator, trem-
bler, or current inter-
rupter. The rate of
vibration of the inter-
rupter can be varied by
adjusting the screw K,

86. In order to get
better contact and a
more rapid separation
of the contact points at
the vibrator of an induc-
tion coil, an lini>act device is used on some coils. One
form of device is shown in Fig. 31 (a), in which a shows the
magnet pole and b the vibrator, which, in this case, is made
of a comparatively thin strip of tempered steel. This steel,
however, is not hard enough to remain a permanent magnet
after magnetization. Instead of having the contact point
located on the vibrator proper, a copper strip c is rigidly
mounted on the frame d, and a knock-off piece e is attached
to the vibrator. When the magnet attracts the vibrator
blade, the latter is drawn toward the magnet some distance
before the knock-off e strikes the end of the contact strip c

Digitized by

Google

50 ELECTRIC IGNITION § 6

and causes the contact points to separate. On account of
the velocity attained by the vibrator before striking the
contact strip, the break at the contact points is more rapid
than can be secured without the aid of some such impact
device. With this particular design of coil a stop / is pro-
vided to check the upward motion of the vibrator and pre-
vent its unnecessary vibration after the current is broken.
The ordinary adjustable contact screw is shown at g.

87. Another form of impact-break vibrator involving
the principle of operation just described is shown in Fig. 31 (6).
In this case, however, the contact strip c is placed on the side
of the vibrator next to the magnet a. The vibrator h is
perforated to allow the point of the adjusting screw e to

Pig. 32

extend through it and press the contact strip c away from
the vibrator h when no current is flowing through the appa-
ratus, the frame of which is shown at d. When current
flows and the magnet a attracts the free end of the vibrator,
the latter moves down, gaining some velocity before it
strikes the contact strip, and suddenly breaks the circuit.

88. An exterior view of an induction coil with a mag-
netically operated vibrator and four terminal binding posts
is shown in Fig. 32. The binding posts a and h are the
terminals of the secondary coil. At c and d are shown the
terminals of the primary coil; at e, the trembler, or vibrator;
at /, a screw for adjusting the vibrator so as to bring the end

Digitized by

Google

ELECTRIC IGNITION

carrying the piece of soft iron either nearer to or farther
away from the end of the core of the coil; at g, the head of
the adjustable contact screw whose point, generally platinum-
tipped, makes contact with the vibrator; and at A, one of
two small screws for clamping g firmly in its threaded hole
through the split yoke that supports it after it has been
properly adjusted. The induction coil and the condenser
are properly connected together and to the terminals, and
are firmly held in place in the box by a mass of paraffin,

which is poured in hot and allowed to solidify. One end
of the core of the coil is brought through the box just xmder
the trembler.

This four-terminal type of induction coil is not much used
on automobiles, because the three-terminal type is more
suitable. It is sometimes used for two spark plugs by
connecting a to the insulated part of one spark plug and b to
that of the other, the metal of the engine completing the

Digitized by

Google

52 ELECTRIC IGNITION § 6

een the plugs, which are connected in series
ment. The coil can be converted into a
iTpe by joining one of the primary terminals
::ondary terminals.

Vibrator. — Instead of providing each coil
sometimes a single vibrating device, called a
or, is used for a number of coils. Such

in which a master vibrator is provided for
ils^ is shown in Fig. 33. All four condensers
^e one of their terminals connected to the
it p c, and each one has its remaining terminal
it end of its own coil which is wired to one
: the timer T. Thus, both the master vibrator

timer contact have a condenser connected
The path of the discharge current from
J be traced from the lower side of the con-
terminal p c, winding of the master vibrator
{ connection pb, battery A, frame of car
mon connecting wire to the terminal p s oi
• No. 1, coil, through the primary winding
^ ps and pi, back to the condenser. The

of any other condenser can be traced in a

oil has a single ' winding, and is therefore
5 double-wound induction coil and is com-
ensive. It resembles a kick coil to which
Ided. The timer in this case has its rotor r
le other parts of the apparatus. The current
y passes through the master vibrator and
rubbing contact piece of metal q, which is
sulated part / of the timer, then through the
between the piece q to the metallic portion r
n which it passes successively through each
*2, *a, and k^ to each primary coil, then to
3, and back to the battery. Current from
Ending of each coil passes from 5 to the
ie of the corresponding spark plug ij, across

Digitized by

Google

§ 6 ELECTRIC IGNITION

the air gap to the uninsulated electrode and thence
the engine to the primary-secondary terminal p s.

If it is not considered necessary to protect the p
the timer by condensers in parallel with them, the f
densers of the similar coils can be replaced by a sin
denser connected around the contact points of the
on the master coil.

Digitized by

Google

Digitized by

Google

ELECTRIC IGNITION

(PART 2)

CUBBBNT-DISTRIBDTING DEVICES

8PABKIN6 APPIilANCBS

IGNITERS

1. The sparking device employed with what is variously
known as the totich-sparky wipe-spark, contact-sparky low-
tensiatiy or make-and-break system of ignition, is commonly
called an Igrnlter, which name distinguishes it from the
sparking devices used with the

jump-spark, or high-tension, system
of ignition.

2. One form of low-tension
contact igrniter is shown in Fig. 1.

The stationary electrode a is insu-
lated from the metal body of the ig-
niter by two pieces of steatite ( soap-
stone). These are bored for the
electrode to pass through and are
coned outside to fit in the hole, which,
as shown, is much larger than the ^'®- ^

electrode and tapers at the ends to suit the insulating plugs.
The rocker spindle b carries the contact finger c, which is
inside the combustion chamber and is connected by the
rocker spindle to the external arm d. This arm pro-

COrrmOHTCO BT INTKRNM-IONAL textbook company. BNTBREO at BTATIONBRB* HALU LONDON

Digitized by

Google

2 ELECTRIC IGNITION §7

vides a means for rocking the rigidly connected parts *, c.

le of operation, as well as the general
echanism for actuating this and similar
in Fig. 2, view (a) being a front eleva-
a side elevation. At a is shown a shaft
turning at one-half
the speed of the en-
gine; or, if the engine
is of the two-cycle
type, it turns at the
same speed, and may,
in fact, be the engine
crank-shaft itself . On
this shaft is a cam d,
frequently called a
snap camy that bears
against a roller c, held
in contact with the
cam by the spring d
on the tappet rod e.
The lower end of this
rod, or plunger, is
threaded, so that by
adjusting the nuts at
/, and thus increasing
^^ or decreasing the dis-

tance that the foot of
o the socket ^, the length of the rod and,
vidth of the gap when the igniter points
iried at will. When the roller c is in its
,w„www ^w^.w*w.*, v*ie ball on the upper end of the tappet
rod e rests in a socket in the lever arm h (corresponding to
d, Fig. 1). This arm is secured to a rocking stem (as d.
Fig. 1) that passes through the wall of the combustion
chamber, as shown by the dotted lines of the side elevation
in Fig. 2 (a). The inner end, which has a ground joint to

Digitized by

Google

ELECTRIC IGNITION

prevent the ceases from blowing past it, is prolonged to the
finger /. This finger makes contact with an insulated
stem y, to whose outer end one of the wires of the electric
circuit is attached. The light spring k holds the finger /
against the stem /, except when the two are separated by
the pull of the head of the tappet rod e in the socket of the
arm h. Because the greater tension of the spring d over-
comes that of the spring k, the contact points are normally
out of contact except when the tappet rod is pushed up by

i^)

(b)

(c)

Pxo. 8

the cam. The adjustment of the tappet rod is such that
after contact has been made it leaves the socket of the
arm h and continues its upward motion a short distance, so
that, when the roller € drops off from the cam, the head of
the tappet rod strikes the arm h a smart blow, thereby
causing an abrupt separation of the contact points.

As shown, the roller c is mounted in a rocker-arm /, one
end of which is pin-connected to a second rocker-arm w,
which is operated by hand to control the time of ignition.
When the arm m is moved toward the right, as indicated by

Digitized by

Google

4 ELECTRIC IGNITION §7

the dotted outline n, the ignition is earlier than when it is in
the position fn\ when m is moved toward the left, to the
other dotted position o, the ig:nition is made later.

4. A make-and-break Ig^nlter desig^ned to be operated
on current from a battery or a low-tension magneto, is
illustrated in Fig. 3. Fig. 3 (a) shows a longitudinal section
of the device, and Fig. 3 (b) shows details of the interrupter
lever and magnetic core of the coil. The hexagon-headed
plug a is screwed into the engine cylinder in the same man-
ner as with a high-tension spark plug. The body b of the
plug contains a spool-wound magnet coil c and the upper end
of the interrupter lever d. The igniting current passes
through the magnet coil, and acts to move the interrupter
l3ver so as to break the circuit and form the spark at the
contact points of the igniter.

The interrupter lever d extends down into the part a, and
has at its lower end a contact points that makes contact with
the stationary part /. The latter is part of a and is therefore
grounded, being electrically connected to the engine. The
magnet core^ carries a knife edge at hy on which the inter-
rupter lever d rocks. A U-shaped spring / presses the inner
parts of its ends against both the core and the interrupter
lever, so as to keep the* contact points e and / together,
except at the instant they are separated to form the spark.
The core g has a brass piece j inserted in it.

5. The electric circuit through the apparatus is from the
terminal k through the conducting plate /, rivet »i, to the
terminal of the coil ^, through the coil to its other terminal «,
which is in electric connection with the magnet core. From
the magnet core the current flows to and through the inter-
rupter lever d to the contact point e and thence to / and the
body of the engine.

When the timer closes the circuit, the current magnetizes
the core g and a magnet pole is thus formed in the region of
the brass insert/. This pole attracts and draws toward it.
the upper end of the interrupter lever d, thus rocking the
lever on its knife-edge support and moving the contact point e

Digitized by

Google

§7 ELECTRIC IGNITION 5

away from /. This breaks the electric circuit and causes a
spark at the contact points. The magnet loses its magnetism
immediately after the circuit is broken, and the contact
points are again pressed together by the U-shaped spring.
They are then ready for the next closing of the circuit by the
timer to form a spark for the next explosion.

The contact piece /, as shown in Fig. 3 (c) has a V-shaped
groove into which the contact e enters with a slight
wedging action. The interrupter lever is allowed a small
amount of side play, so that in case one side of the V of the
contact piece is fouled and does not make electric contact,
there is still the other side remaining with which suitable
contact may be made.

The body a is insulated from e by the steatite cone o and
mica plates p. The makers of the plug recommend that
the part of the engine into which it is screwed be well
cooled by water. ____^

SPARK PLUGS

6. The almost universal form of spark plusr for jump-
spark, or high-tension, ignition consists of a small central
wire or rod that passes through some kind of insulating
material. The insulation is in turn surrounded by a threaded
piece of metal or bushing that screws into a threaded hole
in the engine cylinder. The central wire, or rod, is thus
insulated from the external bushing, within a short distance
ot which the central wire terminates. The space left between
the wire and outer metal bushing is the g^ap across which
the spark jumps. Being in contact with the metal of the
engine, the outer bushing of the plug forms part of the frame-
connected side of the high-tension circuit. Only the central
wire of the plug is insulated from the engine.

In some of the forms of high-tension spark plugs not
extensively used, the electrodes on both sides of the spark
gap arc insulated from the engine, and in this way double
insulation is provided between the electrodes and terminals
of the wires leading to the plug. Two connecting wires are
necessary for each plug when double insulation is thus used.

Digitized by

Google

Fi« 4

Digitized by

Google

§7 ELECTRIC IGNITION 7

7. The width of the spark gap is generally about iV inch
for spark plugs used in connection with induction coils pro-
vided with magnetically operated vibrators. In one or two
very unusual cases, the makers of such vibrator coils recom-
mend that the spark gap be as wide as A inch when the
batteries supplying current to the induction coil are new and
of full strength.

For use in connection with magneto-electric generators
and non-vibrator coils, or transformers, it is generally recom-
mended by the makers of such apparatus that the width of
the spark gap be from A to A inch; these values correspond
approximately to .4 and .5 millimeter.

8. The material used for insulating the parts of the
spark plug from each other is usually either porcelain, mica,
or steatite. The threaded bushing is ordinarily made of
steel, brass, or bronze and the central wire of steel. The
inner end of this central wire is quite frequently terminated
with a piece of platinum wire.

As found on the market, the sizes of the threaded bushing
vary considerably. Many plugs are of the size that corre-
sponds to i-inch gas pipe; the outer diameter for i-inch gas
pipe is approximately i inch. The gas-pipe thread is tapered,
and for this reason no shoulder is required to make a gas-
tight joint between the plug and engine. In other plugs, the
thread is of uniform diameter, and a shoulder and copper
washer are provided, as shown in Fig. 4 (a), for making
the joint gas-tight. The thread is similar to that on a
machine bolt or screw. These plugs are about the same
size as those with the i-inch gas-pipe thread. Quite a
number of plugs in millimeter sizes are used; some are
larger and some are smaller than the s-inch gas-pipe thread
already mentioned.

9. Fig. 4 shows a number of spark plugs for jump-spark
ignition. In (a), the steel bushing a is the part that screws
into the threaded hole in the engine cylinder. At b is
shown the porcelain insulator; at r, a threaded bushing
for clamping the porcelain and packing into place; at d, a

222B— 22

Digitized by

Google

8 ELECTRIC IGNITION §7

packing: ring of copper, asbestos, or some other suitable
material; at e, the central insulated wire, or electrode; and'
at /, a binding-screw terminal for connecting the external
wire. The spark gap is between the curved end of the
central insulated wire e and the grounded wire g projecting
from the bushing a.

The construction of the plugs shown in {b)y {c), (d), (^),
and (/) is but little different from that shown in (a). What
is known as a closed-end plug is shown in (^), the points
a and b being located in the nearly closed end of the plug.
The point a is concentric with the plug-end opening into
which the point b projects from one side. The so-called open
type of the same plug is shown in {c) , the point a projecting
beyond the end of the plug, as shown. The point b can be
turned away from a to increase the gap between the points.
In the plug shown in (^), the point a is mounted in the
hexagonal head b of the insulated bolt c for conducting the
current and for keeping the plug tight, the spark bridging
the gap between the point a and the threaded shank of the
plug. In the plug shown in (^), the insulated electrode a
resembles a star. The spark occurs between the projections
of the insulated electrode a and the threads of the grounded
electrode b. In the plug shown in (/), the insulated elec-
trode a is threaded and the opening ' b of the grounded
electrode is star-shaped. In the plug shown in (^), the
insulated electrode a is wrapped with sheet mica ^, and then
surrounded with mica washers c pressed closely together
under heavy pressure and held in place by a brass nut d and
washer. The grounded electrode e is fastened in the bush-
ing /. Spark plugs are sometimes protected against the
short-circuiting effect of moisture by means of a porcelain
hood, or cap, a. Fig. 4 (A). This cap has a recessed neck b
on one side to receive the wire c, which is connected to the
plug by a terminal link d in the manner shown.

Digitized by

Google

§7 ELECTRIC IGNITION

AUXII.IARY SPARK GAP

10. A spark plug whose insulation has become some-
what defective can sometimes be made to perform its service
by connecting in series with the gap at the spark plug a
device known as an auxiliary spark, gap, two forms of
which are shown in Fig. 5. This device consists simply
of two insulated terminals a and o, with points separated by
an adjustable gap, usually about iV inch in length. In the
form shown in (a), the terminals are enclosed in a glass
tube c to prevent possible ignition of stray gasoline vapor.
This form is connected in the secondary circuit by means of
the connecting screws d and e. The form shown in {b) is
attached to the binding post of the spark plug itself, and the

Pio. 6

spark jumps from the point a to the binding post b. The
base / is made of fiber.

When the primary circuit is broken by the timer, it
requires a short time for the induced current in, the second-
ary circuit to build up to its full voltage; and, in order that
the full voltage may be reached, it is necessary that the first
small quantity of energy induced in the secondary shall not
be allowed to escape. If the spark-plug insulation is not
perfect, or if the plug is sooted, the charge first induced
leaks away either through the insulation or over the soot
deposit, and the voltage does not become great enough to
force the current across the gap and produce a spark. By
the use of an auxiliary spark gap outside the cylinder, the
secondary circuit is held open, this leakage is prevented, and

Digitized by

Google

10 ELECTRIC IGNITION §7

the induced current builds up to its proper voltage. Thus,

ergy of the
rk.

as they are
ition circuit
ution of the
insure igni-
engine is of
principle of
it the length

the time of
t life of the

l^aLlCiy 13 Lil^ l^OUAfc,*

Almost innumerable forms of timers are in use. One of
the features of chief importance ik the method of making
contact between the rotor and the stationary member.
Sliding contact is used to a considerable extent, and steel
balls are also used for contact. In most cases the rotor is
electrically connected to the driving shaft, but in some
designs it is insulated from the machinery and frame of
the car.

Digitized by

Google

§7 ELECTRIC IGNITION

The most essential requirement to be met by a i
that, for a given setting, it shall always close the
circuit at the same instant relative to the movemer
engine piston. This is called sytuhronous operation.
timers fail in this respect after some service, the faih
erally being due to worn or loose parts that can move
extent without restraint. With the timer illustrated i
such failure is not likely to occur in case of wearin
roller and pin that holds it, because the spring atti
the arm always keeps these parts pressed together,
such as a roller and its pin, that are not pressed tog
this manner are liable to give trouble when wear
Also, wear between the stationary parts and the shai
timer may cause some irregularity in the time of ign

12, The timer shown partly in section in Fig. 6
primary electric circuit at each instant that a spark
produced in the engine. The casing, or housing, of th
consists of a large wood-fiber disk a, with a thick raise
in which are embedded four brass contact pieces c,
which i§ provided with a terminal for connecting
proper spark coil. The shaft that supports the tin
through the disk a, which has a bearing on the si
carries a hub d, to which is pivoted a lever e. One
the lever e carries a roller / that runs against an
ring h and makes contact with the insulated segmen
spring g connected to the other end of the lever e
good contact. An arm h projecting from the bod;
timer is provided for making connection to a system
These links prevent the rotation of the disk a, and at t
time afford a means of changing the instant of
through movement of the hand-operated spark conti
at the steering wheel, not shown. A cap is prov:
covering the parts of the timer and protecting the
dust. This cap also affords a means of retaining
grease for lubrication.

Digitized by

Google

12 ELECTRIC IGNITION 87

DI8TRIBUTOBS

13. Distributors, or secondary commatators, are

Digitized by

Google

§7 ELECTRIC IGNITION 13

all other parts of the apparatus and of the automobile. The
spark plugs are connected to stationary insulated terminals
I, 2, 3, 4 of the distributor. As the distributor arm turns
about its axis, its broadened end passes successively over
these terminals, either making metallic contact with them or
coming very close to them. The rotor r of the timer and
the arm d of the distributor rotate at the same speed, so
that when the timer closes the primary circuit, the end of the
distributor arm is over one of the terminals 1, 2, 5, 4. The
high-tension current passes between the distributor arm and
the terminal that it is over, and is thus directed to the cor-
responding spark plug. Through the rotation of the dis-
tributor arm, the current is distributed successively to the spark
plugs of a four-cylinder engine in either the order 1, 2, 4, 3 or
3y 4, 2, 1, according to the direction of rotation of the arm.

Since the current passing between the distributor arm
and the stationary terminals has sufficient tension to jump
the gap at the spark plug, it will also jump a small gap
between the distributor arm and terminal in case they
do not touch each other. In fact, a small air gap here is
sometimes considered an advantage for the reasons given in
connection with the description of auxiliary spark gap
devices in Art. 10.

The timer rotor r and the distributor arm d are generally
mounted on the same spindle, or shaft, but they are
thoroughly insulated from each other. If they are mounted
on separate shafts, the timer rotor may have only two con-
tact points and may rotate twice as fast as the distributor
arm; or, it may have only one contact point and may rotate
four times as fast as the distributor arm. The free end of
the distributor arm is broadened circumferentially, in order
that some part of it will always be over one of the cor-
responding terminals when the timer closes the primary circuit,
although the contact piece k of the timer is rocked through
a considerable arc (45° or so) to vary the time of ignition.

14. Spark coils of both the transformer, or non-vibrator,
type and the vibrator type, are used in conjunction with a

Digitized by

Google

IGNITION §7

tor type of coil is used, the

at the vibrator, is somewhat

ibrator must perform as much

m individual spark-coil system

for four spark plugs. Under

this condition, the vibrator

contacts are much more liable

to become burned and fused

than when the work is divided

anjong: the four vibrators of

the individual-coil system.

If the coil fails to operate
because of this or any other
reason, ignition current is
cut off simultaneously from
all the spark plugs, and, un-
less provided with more than
one ignition system, the en-
gine under ordinary condi-
tions will stop immediately.
The possibility of this occur-
rence is recognized by the
makers of such ignition de-
vices, and a spare coil is often
provided in the box enclosing
this part of the ignition ap-
paratus.

In a vibrator coil used in this

manner, the condenser can

aly the vibrator contact points.

jft without the protection of a

practice for battery currents.

DUtor is mounted on the same
lows this arrangement in sec-
mary contact is made by a
y a spring, as shown. The
ire carried on a shaft turning

Digitized by

Google

§7 ELECTRIC IGNITION 16

at one-half the speed of the crank-shaft of a four-cycle
engine. The cam has four lobes for a four-cylinder
engine of this class. The secondary current is led to
the binding post d, through which it travels, by way of
the contact ball ^, to the brass strip / that runs over the
hard-rubber surface g, and makes contact with the flat-
headed screws h embedded therein. These screws carry
the current to the several spark plugs.

Efficient insulation between the primary and the secondary
is secured by the long, hard-rubber stem / on which the brass

Pio. 9

strip / is carried. The casting / is rotated by the arm k
to advance or retard the spark. It is evident that a rock-
ing movement of this arm either advances or retards both
primary and secondary contacts alike. A ball bearing / is
shown between the spindle and the part c,

16. In the combined timer and distributor shown
in Fig. 9, the shaft a carries at its extreme end the timer
cam b, which has as many lobes as there are spark plugs to
be supplied. These lobes successively make contact with
the steel plunger c. This plunger is supported in a hard-
rubber casing dy and by means of a sleeve is fastened on a for
rocking according to the spark advance required. Attached

Digitized by

Google

16 ELECTRIC IGNITION §7

to a by a taper pin is a hard-rubber barrel ^, carrying a con-

Dund it and connected through
igle contact segment near the
Dudary current is carried to the
5r g^ and four other plungers
successively with the segment
•rubber mounting affords efB-
iit-hand end of d is screwed a
jects an arm for rocking d to
The light casting / affords a
the ring A, and can be screwed
le shaft a being operated by a
from the cam-shaft. A glass
ion of the timing cam may be

pk Generator. — A combined
and secondary, or high-tension,
lich differs considerably from
that of ordinary types, forms
the principal part of the appa-
ratus shown in Fig. 10, which
is known as an Atwater-
Kent spark grenerator.
Besides the combined timer
and distributor, this device
includes a coil of the trans-
former, or non-vibrator, type
and a condenser. The whole
mechanism is enclosed in a
box, or case, a, so as to form
a single unit that is bolted to
the dash. On the bottom of
the box, at the right, are two
binding-post terminals, to
which are attached the wires
erminals of a dry-cell battery
terminal wire is connected

Digitized by

Google

§7 ELECTRIC IGNITION 17

to the binding post nearest the dash, and the wire from the
carbon-plate terminal is attached to the binding post shown
at b. The secondary is grounded within the device, and for
this reason no ground wire is necessary.

The timer, or primary contact maker, the distributor, and
the spark-advancing device are carried by a single vertical
shaft c in the left-hand side of the box. This shaft is driven
from the cam-shaft, timer shaft, or other rotating part of the
engine by means of gears and shaft with universal joints.
With four-cycle engines, this shaft rotates at the same speed
as the cam-shaft, but with two-cycle engines, it is driven at
the same speed as the crank-shaft.

18. When the primary circuit is broken by the contact
maker, the induced secondary current passes from the coil in
the right-hand side of the box to the distributor shaft c
through a brush in the brush holder d, the brush being
held in contact with the shaft by means of a spring. From
the shaft c, the secondary current is delivered by some one
of the four brass distributor blades e to some one of the four
secondary terminals and connected binding posts /, to which
are attached the wires leading to the spark plugs. These
wires are carried through holes in the dash and the back of
the box. The distributor blades ^, which do not touch the
terminals, are insulated from the rest of the shaft, and the
secondary terminals to which the binding posts / are attached
are also insulated. Opposite each of the secondary terminal
binding posts is a spring-actuated button g. This button,
when pressed inwards, grounds the spark for the corre-
sponding cylinder of the engine, the plugs of which may
thus be tested. When trouble from skipping is experienced,
the cylinder that misses may be easily located by alternately
depressing the four cut-out buttons; the one whose depres-
sion does not affect the firing of the other cylinders corre-
sponds to the cylinder that misses.

The spark plug of the first cylinder, in which the charge is
to be exploded, is connected to the terminal opposite the
upper distributor blade, the plug of the second cylinder is

Digitized by

Google

ELECTRIC IGNITION

connected to the terminal of the distributor blade that next
comes to its terminal, and so on. The spark is advanced
or retarded by means of a spiral sleeve actuated by the
shaft h, so as to turn the upper part of the shaft c^ where
the contact device, or timer, within the case t is attached.
For starting the engine **on the spark," the contact maker is
provided with a starting lever that has a button /. This

Pio. 11

button, when pressed, makes contabt, and when released,
produces a spark in the cylinder that happens to be in
communication with the distributor. The contact should be
made and broken by a tapping motion of the fingers on the
button y. The cover over the contact maker is held in place
by a wing nut k, while the generator box is fastened to the
dash by means of bolts passing through holes /, of which
there are two on each side. The battery switch m is mounted

Digitized by

Google

§7 ELECTRIC IGNITION 19

on the front of the box, as shown, the removable switch
plug n being located to the right of the switch lever o. An
oil tube p provides for lubrication^ while the clamping collar g
provides a means of setting the time of the spark.

19. A plan view of the mechanism of the primary con-
tact maker, or timer, of the Atwater-Kent apparatus is
shown in Fig. 11 («), different positions of the working
parts being shown in (^) and {c). There are three moving
parts, namely, the shaft «, the snapper ^, and the pivoted
contact arm c. In the end of the shaft a, which is the upper
end of the shaft c. Fig. 10, are four notches that form a
ratchet. This ratchet engages the claw at the end of the
snapper by which is a light piece of tempered steel that is
guided in its movement by slots in the bronze base de and
is pulled by the spring / against a spring-wire stop g when
released from the notches on the shaft. The contact arm c
is normally held in the position shown in Fig. 11 {a) by the
spring h. The shaft «, turning counter-clockwise, draws
the snapper b into the position shown in (b)y the claw of the
snapper riding up out of the notch of the ratchet on to
the rounded part of the shaft, as shown in (c). In this way,
it acts as a wedge between the shaft and the steel hook / of
the contact arm, which is pivoted at /, and brings a platinum
point in the flat copper spring k into contact with the
insulated stationary contact screw /, thus closing the primary
circuit. Under the pull of the spring /, the snapper claw
is then quickly snapped into the next notch of the shaft,
releasing the hook / and thereby suddenly breaking the
contact at the platinum points on k and /. The snapper
and contact arm thus come to rest in their normal positions,
as shown in Fig. 11 {a).

With the engagement of the snapper claw by the next
tooth of the ratchet, the process of making and breaking the
circuit is repeated, the period of contact being the time
required for the snapper b to slide past the hook i. The
duration of contact, which is always brief, may be varied by
turning the contact screw /. No spark is produced in

Digitized by

Google

20 ELECTRIC IGNITION §7

turning: the shaft a in a direction opposite to its normal, or
counter-clockwise, rotation, because the snapper will clear
the hook of the contact arm when the shaft is gfiven a clock-
wise rotation. This non-reverse feature is of value with
two-cycle engines,* which will start backward **on the spark"
as readily as forward when an ordinary timer is used. There
is nothing about the device that requires adjustment, except

the contact screw /, a close setting
of which prolongs the duration of
contact, because the contact is
sooner established on return of the
snapper. Adjustment of the con-
tact screw permits of a light con-
itact with a fresh battery, while with
the maximum length of contact,
cells that would ordinarily be con-
sidered depleted may be utilized,
because there is no waste of
energy in the production of more
than one spark, which is all that
is needed to ignite a combustible
**' mixture. In the ordinary service,

after adjustment for use with a fresh battery, the contact
points should be brought nearer together by giving the
contact screw / a quarter or a half turn every 500 miles.

20. In Fig. 12 is shown a more compact form of the
primary contact maker and the distributor elements of the
apparatus shown in Fig. 10. In this case, the non-vibrator
coil, condenser, and switch are arranged in a separate unit
attached to the dash. This device is adapted for use on cars
where it is inconvenient to install the spark generator, and
takes the place of an ordinary timer on any convenient half-
time shaft. The hard-rubber distributor casing a carries
four posts b, to which the spark-plug cables are attached.
Two primary wires are run in the cable c, from the coil to
the contact maker, and a central post d receives the high-
tension current from the coil and transmits it to the dis-

Digitized by

Google

§7

ELECTRIC IGNITION

tributor blade. This blade is fastened to a hard-rubber
block removably mounted on the contact-maker shaft. For
advancing and retarding the spark, the body of the contact
maker is actuated by the lever e in the usual way.

SWITCHES

21. Small hand switches, such as are used on auto-
mobiles in the primary circuit for two batteries, are shown in
Fig. 13. In the switch shown at (a), the positive terminals
of the two batteries are attached at the back to the con-
tact points a and b, respectively, so that, when the switch
arm c is in contact with either contact point, current will flow
through the switch
arm c and plug d^ shown
in full in the side
view (^), to the spark
coil, and from thence to
the timer and through
the grounded timer
shaft back to the
battery. The switch
arm, or lever, r. Fig. 13
(r), is removable, and ^^

is shown separated
from the base of the
switch, Fig. 13 (^),
to which it belongs.
When put into use, the
pin, or plug^is inserted
in the round hole shown
just back of the base
plate. When the pin
is thus inserted, the
wedge-shaped contact
point on the switch
arm c can be brought
against either the contact piece a or the contact piece b or
between the two at the space marked e. The part with which

(c)

Pig. 18

Digitized by

Google

§7

ire
)n-
be
he
he

contact piece of c in the space e between a and ^, so tnat
the sides of the wedge press against both of these parts, the
batteries will be in parallel. A small notch near the middle
of each of the contact pieces serves to hold the lever in
position when the knife edge bears in the notch.

Digitized by

Google

§7 ELECTRIC IGNITION 23

22. A two-battery swltoli bavins: five positions for its
lever arm, including the off-position, is shown in Pis:. 14.
The four working positions correspond to: (1) battery A in
circuit alone; (2) battery ^ in circuit alone; (3) batteries^
and B in parallel; and (4) batteries A and B in series.

A plug a fits into the hollow pivot of the switch arm. The
withdrawal of this plug breaks the electric circuit, so that the
switch becomes inoperative. In (b) is shown the switch
connections for an individual-coil, high-tension ignition
system. The switch is generally placed near the spark
coil C from which the secondary wires are carried to the
spark plugs D. A wire is led from the binding screw a to one
primary terminal of each spark coil. In this case there are
four coil terminals. When the switch arm is on contact
button by the circuit is open; when on r, battery A only is cut
in; when on d, battery B only is in circuit; when on e, the
batteries are operating in parallel; and when on /, the batteries
are in series.

The connections, in addition to those already given, are as
follows: From the carbon plate of the right-hand end cell of
battery A^ a wire is carried to the binding screw r, the wire
from the carbon plate of the right-hand end cell of battery B
being carried to the binding screw e, under which is a link, or
contact strip, s connecting with the contact points d and /.
Thus far, the same letters of reference apply to similar parts
in {a) and (b). A wire from the zinc of battery A is con-
nected to the binding screw g attached to the metal plate h,
and a wire from the zinc of battery B is connected to the
binding screw / attached to the metal plate /. In a fiber
plate k fixed on the post a. Fig. 14 (a), so as to turn with it
when the switch arm is shifted, are mounted three contact
pins /, w, and «, Fig. 14 (^), that slide on the metal plates h
and y. These pins are electrically connected by means of a
wire o laid in a slot in the fiber plate k and soldered to
the pins.

23. When the end of the switch arm rests on the contact
point c, current flows from battery A to c, then through the

222B— 23

Digitized by

Google

24 ELECTRIC IGNITION §7

;o coils C and by grounded
tery A, When the switch
ttery B to <f, thence through
itch arm to a, to coils C to
^ screwy and plate h^ pin y.
:ew / and wire «, back u>
\ rests on e, it also make>»
point V, Fig. 14 (a), which
neans of the metal plate w,
lates of the right-hand end
as connected together, the
left-hand end cells of the
two batteries being con-
nected by means of the
contact pins /, m, and «,
wire o, plates h and /.
The batteries being thus
connected up in parallel,
current flows through
binding screws and switch
arm to a, then to coils C,
grounds g and r to bat-
tery Ay and to battery B,
by way of wire /, binding
screwy, plate h, pins /, m,
5w iy and wire u. When
hifted into contact with /,
with the plate k, while the
3tal plate x, thus connect-
:he zinc of battery By and
jeries. Current then flows
m plate of the right-hand
rough plate s to /, through
unds q and r, back to the
ms completing the circuit.

wo sources of current are
ies and coils are installed

Digitized by

Google

§7 ELECTRIC IGNITION 25

together with a magneto, is shown in section in Fig. 15.
By throwing the switch handle a to one side, the magneto
circuit is closed and the magneto is in operation; throwing
the switch handle to the other side cuts out the magneto,
closes the battery-and-coil circuit, and places the batteries
and coils in operation. The ball contacts b are held against
the contacts c by the springs dy and are in electrical connec-
tion through the strip e. Wires from the two sources of
current are led to the binding screws / and ^, the common
circuit-completing wire being attached at h,

25. A slnsrle-tliroTr, tTTo-poIe, knife s^v-ltcli, or
blade switch, is shown in Fig. 16 (a). The two blades a
and b are insulated from each other, and hinge on pins
through the posts c and d. The lips of each of the other
two posts e and /
press against the
blade between them
with a spring action,
so as to make good
electrical contact. As
ordinarily used, one
side of the switch, as *'*''

f, tf, and e, is inter-
posed in one side of
an electric circuit,
and the other side d,
by f in the other side
of the circuit. Thus,
if used on a battery

circuit, the positive »-^

wire from the battery ^'®- ^®

can be connected to Cy and the negative wire to d. The
wires leading out to the other part of the circuit are then
similarly connected to the posts e and /, respectively. When
the switch is opened by lifting the handle and blades, both
sides of the circuit are broken. The term two pole is used
because both sides of the circuit are connected to the switch.

Digitized by

Google

26 ELECTRIC IGNITION §7

26. A double-tliroTV', tTro-pole» blade sTivitoli is

shown in Fig. 16 (d). It diflEers from the single-throw
switch just described in that it has another pair of posts to
which a second pair of wires can be connected. If used with
two batteries, either of which is to supply current to a piece
of electrical apparatus, the wires from one battery are con-
nected to the posts e and /, and the wires from the other bat-
tery to posts ^ and k. The connections to the apparatus are
made at c and d. Either battery can be put in circuit with
the apparatus by throwing the blades to the corresponding
position. The term double-throw is applied to the switch
because it closes a circuit in either of two positions.

Blade switches are not much used on automobiles, but
apparatus for charging storage batteries is generally equipped
with them.

INSUXATED WIRES AND WIRE TERMINAIiS

27. The insulated conductors used in automobiles are
generally made in the form of wire cables having a rather
large number of strands. The chief difference between those
for high-tension current and those for low-tension current is
in the thickness and electric pressure-resisting qualities of

ii>^»»fm>f>^

the insulation. From an electrical standpoint, the high-
tension cable does not need near so much copper as the low-
tension one, but is made heavy enough to give it strength
to meet mechanical requirements.

28. Typical insulated copper cables are shown in
Fig. 17. The primary, or low-tension, cable is shown in (a).
The wire core of the cable consists of forty strands of No. 30
tinned copper wire. The insulation consists of one layer

Digitized by

Google

§7 ELECTRIC IGNITION 27

of high-grade vulcanized rubber a, and the protective cov-
ering consists of two braids c and d covered with two layers
of enameled coating baked on. It would take about 12,000
volts to puncture this insulation. The core of the high-tension
cable (b) is the same as that of the low-tension cable. The
insulation consists of three layers of rubber a, b, c vulcanized
together. The rubber is protected by two braids e and /,
covered with four coats of enamel baked on in steam-heated
ovens. The enamel forms a flexible, insoluble film that pro-
tects the rubber from heat, oil, and water, and the braid
protects the cable from mechanical injury. More than 40,000
volts is necessary to puncture the insulation of this cable.

29. Copper or brass terminals are generally attached to
the ends of insulated wir6 conductors. For the primary low-
tension cables, it is essential to have good metallic contact.
This is readily secured by using a drop of solder to fasten
the wire and terminal together at one point. It is not neces-
sary generally that the solder shall make a strong mechanical
connection. On high-tension ca-
bles, soldering between the cable
and terminal is never necessary,
so far as the electrical connections
are concerned. The high-tension
current will jump any ordinary pio. ig

small air space that may occur between the different metallic
parts. Soldering may be desirable, however, in some cases,
to hold the parts together. The terminal piece should be
provided with clips, a ferrule, or some corresponding device
that will firmly grip the insulation and thus relieve the
mechanical stress on the wire core, so as to secure a connec-
tion not liable to breakage.

30. Good battery connectors may be made up from No. 16
flexible lamp cord in 8-inch lengths. The cord is untwisted for
the purpose, and each length makes two connectors. The ends
of the cords are scraped for a length of about 1 inch, and the
bare wire twisted and doubled on itself. The wire is then
slipped through a terminal or copper connector of the form

Digitized by

Google

28 ELECTRIC IGNITION §7

* *"' - '^ • ' e end being run through the stamped
[lammered flat, the wire doubled back
ent over the insulated part of the wire
^ire is then coiled around a lead pencil,
m the battery cells show a tendency
[nay be locked with nuts taken from
ever the* wire connections are flex-
escribed, and the cells do not shake
e tendency on the part of the nuts

lSuring instruments

I Voltmeters. — In connection with

instruments used for measuring the

iperes, called ammeters, and pres-

called voltmeters, are generally

enient form for carrying, frequently

a watch. Their accuracy need not

be very great. Such instruments

are often combined into one,

measuring both the current

strength and the pressure, in

which case they are called

Toltammeters.

32, A simple form of instru-
ment for measuring either volts or
amperes, or both, according to the
winding of the coil through which
the current flows in any case, is
shown in Fig. 19. For con-
venience of description, it will first
be assumed that the instrument
uring amperes of current. A coil
md on a stationary spool, as shown.
, or rod, b is rigidly fastened to the
wound, and a spindle c is pivotally
ary parts d. At e is shown a sheet-

Digitized by

Google

§7 ELECTRIC IGNITION 29

iron vane carried by the spindle Cy and at /, a spiral sprins:,
one end of which is connected to the spindle and the other
to the stationary spool of the coil. All the parts except b
and e are of brass or some other non-magnetic material.
The spindle c and vane e are free to turn on the conical
bearingfs at the ends of c, except that this motion is resisted
by the spiral spring /. The mounting of the spindle c is
somewhat the same as that of the spindle of the balance
wheel of an ordinary time-keeping watch. In the position
of the parts e and c as shown, there is no tendency for the
spring / to rotate c and e in either direction.

When an electric. current flows through the coil a, both the
iron wire b and the vane e become magnetized. The action
of the magnetizing current is such that the poles formed in
these two parts are at adjacent ends. Thus, if the upper
end of ^ is a north pole, the upper end of e will also be a
north pole; and the lower end of each will be a south pole.
The adjacent magnetic poles repel each other. This repul-
sion causes e to swing away from b in the direction indicated
by the arrow. This movement of e and c is resisted by the
spring /. The larger the current that flows through the coil,
the greater will be the movement thus given to e. By con-
structing the apparatus in suitable form, the rotation of ^can
be made approximately proportional to the amount of current
flowing through the coil a, thus affording a practical means
of determining the strength of current. As such instruments
are ordinarily constructed, an index finger, resembling the
hand of a clock, is attached to the spindle c and registers on
a scale suitably divided and marked to indicate the amount
of current flowing. Such an ammeter is connected in series
with the apparatus through which the current to be measured
is passing, so that all the current flows through the ammeter.

33. If the instrument is to be used also as a voltmeter,
then another winding g of thin wire and many turns, so as
to have a high electric resistance, is added. When used to
measure voltage within the range of the instrument, the
resistance of this winding is thus made high enough to pre-

Digitized by

Google

30 ELECTRIC IGNITION §7

vent the flow of current through it to an extent that is
appreciable in proportion to the current capacity of the

battery or other source of elec-
tric current on which pressure
measurements are taken.

The reading: of the volts
is taken by the same index
pointer as is used for am-
peres, but another scale is used,
as shown in Fig. 20.

34. Small, portable instru-
ments for measuring the amper-
age and voltage of electric cir-
cuits are useful in determining the condition of batteries, the
current consumption of coils, and the behavior of dynamo-
electric generators that are used to furnish direct current for
ignition purposes. Such an instrument as is shown in Fig. 20
is used in testing bat-
tery cells by touching
the part marked carbon
to the carbon (positive)
terminal of the cell, and
the insulated cable a
to the zinc (negative)
terminal, which short-
circuits the cell. The
instrument indicates
amperes only when the
button b is pressed.
The button should be
pressed for an instant
only, barely long
enough to allow the

needle to come to rest, as a cell is very rapidly depleted by
short-circuiting.

35. Hoyt Voltammeters. — An instrument of higher
grade than that illup<^rated in Fig, 20, and known as a Hoyt

Digitized by

Google

§7 ELECTRIC IGNITION 31

voltammeter, is shown in Fig. 21. It is provided with
one voltmeter scale, reading from 0 to 10 volts, and two
ammeter scales, one reading from 0 to 30 amperes, for
testing battery cells, and the other from 0 to 1.5 amperes,
for testing the current consumption of spark coils. The
binding post a is for the positive connection, whether for
amperage or voltage testing, the right-hand post b being
negative for the 30-ampere scale, post c negative for the
voltage scale, and post cf negative for the 1.5-ampere scale.
For making test connections, two cable connectors are sup-

Fio. 22

plied, one for tests requiring the use of the high-amperage
scale and one for tests with the low-amperage scale.

This instrument operates on what is known as the
D'Arsonval principle. A permanent magnet is employed to
create a strong magnetic field of practically unvarying inten-
sity. Within this magnet a rectangular coil of fine wire,
wound on a centrally pivoted, aluminum, open-frame bobbin
mounted between the pole pieces of the magnet, is made to
rotate against the opposing influence of a spring by the cur-
rent that passes through it. Attached to the coil bobbin or
frame is a pointer that moves over a scale so graduated as

Digitized by

Google

ELECTRIC IGNITION

§7

to indicate the strength (amperage) or the pressure (voltage)
of the current that causes a deflection of the coil from its
normal or zero position.

36. Another Hoyt instrument, operating on the same
principle as the one just described, but designed to form an
integral part of the ignition circuit, is shown in Fig. 22. It
consists of an ammeter, at the left, and a voltmeter, at the
right, mounted on a common base that is permanently

•JiSis) UfiW

TWSi

OZD 6^

OOO

CZID

Pio. 28

attached to the dash of the automobile by screws, provided
the dash is of wood. In case the dash is of metal, the
instrument is attached to an insulating block on the dash.
Making the instrument a permanent part of the ignition circuit
puts the operator of the car in possession of a continuous
and visible record of performance; in this way, faults that
could not otherwise be quickly traced and eliminated can be
readily detected and remedied under working conditions
oftentimes while the car is in actual operation.

Digitized by

Google

§7 ELECTRIC IGNITION 88

37. In Fig. 23 is shown a conventional diagram that
illustrates how the voltammeter shown in Fig. 22 is connected
up. As will be observed, the carbon, or positive, terminal
of the dry-cell battery Ay and the positive, or plus( + ),
terminal of the secondary, or storage, battery B, are connected
to terminals of the coil c. From these terminals wires are
led to the timer d^ by means of which the primary circuit is
closed. From the block carrying the contact screw of either
of the units of coil r, a wire is led to the right-hand binding
post of the voltammeter. The zinc, or negative ( — ) , termi-
nals of both batteries are connected to the center, or negative,
binding-post terminal of the voltammeter, instead of the
ground, as is customary. The ground, or return-circuit, wire
is attached to the left-hand binding post of the voltammeter.
Current from the primary dry-cell battery A, or from the
secondary battery By whichever may happen to be in use at
the time, passes through the primary winding of the coil c
when the circuit is closed by the timer d. This current also
passes through the voltammeter e and engine /, through
which the return circuit is completed, as is indicated conven-
tionally by the dotted line from the timer shaft to the ground-
wire connection on the engine. The direction in which the
current flows is indicated by the arrows. From the coil r,
tnrough the wire attached to the right-hand binding post, cur-
rent flows into the voltmeter and out to the center binding
post, and from this point it flows back to the battery. When
the timer closes the circuit through the coil, a part of the
current that flows through the timer shaft and ground wire
attached to the engine and left-hand binding post, passes
into the ammeter and out to the center binding post and then
back to the battery. Most of the return current passes
directly from the left-hand binding post to the center binding
post through an insulated by-pass or short-circuit connection^
or shunt, on the back of the mounting.

Ordinarily, the method of wiring shown in Fig. 23 will cor-
rectly connect the instrument in circuit. However, with some
types of coils, for example, the Kingston, the wire leading to
the right-hand, or voltmeter, binding post must be attached

Digitized by

Google

ELECTRIC IGNITION

§7

to one of the hexas:on nuts on the bottom of the coil box.
Instead of the contact-screw block, the copper or brass strip,
by means of which the several units of some standard makes
of coils are connected on the top, may be also used as a place
of attachment for the wire leading: to the voltmeter.

IGNITION STSTEMS

liOW-TENSION IGNITION

38, Make-and-Break, or Contact, System. — If the

ends of two wires forming part of an electric circuit are
brought into contact, thereby closing the circuit, and then
quickly separated, a bright spark will be produced as the
contact is broken. This phenomenon underlies the opera-
tive principle of what is variously known as the toucb-
spark, ipvipe-spark, loipv-tenslon, contact, or make-
and-break, system of is^nltion, with which it is necessary
first to complete the electrical circuit through the spark-
producing mechanism, or igniter, and then break the circuit
to obtain a spark for igniting the charge.

39. A contact-ignition system with battery current is
shown diagrammatically in Fig. 24. The battery is illus-
trated conventionally
at A and the kick coil
at b. The igniter
contact points c and d
go inside the cylinder,
and the stationary rod ,
or electrode, e, which
carries the contact
point r, is surrounded
by mica or steatite

Fig. 24 iusulatiou /, where it

passes through the cylinder wall. The rocker-arm g is con-
nected to the spindle ky which passes through the cylinder
wall and carries the outside member /. The three parts d^ g^

H> :r

Digitized by

Google

§7 ELECTRIC IGNITION 36

and h are rigidly fastened together, and h is free to turn, or
rock, in the stationary metallic bearing that surrounds it.
A leaf spring/ is rigidly attached to /, and engages with the
ignition timer cam k, whose shaft / is supported by some
stationary part of the engine. One terminal of the battery
is connected to the frame of the automobile at m. The
dotted line indicates the electric connection between m and h
through the frame and other parts in metallic contact with
the frame. At n is shown a hand switch that, when closed,
completes the electric circuit, except at the contact points
c and d. This switch is kept permanently closed during the
operation of the system. The coil-spring p pulls the contact
point d away from c.

40. When the contact points afe pressed together, the
path of the current is from the battery A through the kick
coil by the switch n\ to the stationary rod e of the igniter,
then to c, d^ gy and h, and through the parts of the engine
and frame to m^ and back to the battery. The current may
flow in the opposite direction if the battery is connected in
the reverse way. It is immaterial which way the current flows.
When the cam rotates in the direction of the arrow, it lifts
the spring / and rocks the arm g so that the contact point d
is brought against ^, thus completing the circuit when the
switch n is closed. The elasticity of the spring / prevents
undue pressure between the contact points.

As the cam continues to rotate, the lobe of the cam passes
from under /, and the spring action of /, together with the
pull of the coil spring p, separates the contact points rapidly.
This rapid separation is conducive to the procuring of a hot
spark suitable for ignition, without burning the contacts as
much as when the separation is slow.

41. It is desirable that the time during which the con-
tacts are pressed together shall be as short as possible, in
order to prevent unnecessary demand for current from the
battery and possible heating and fusing of the contact points,
especially if the contact is not good, as is often the case.

Digitized by

Google

ELECTRIC IGNITION

§7

The igniter is generally made adjustable by hand with
:he time at which the spark is made in relation to
n of the piston of the engine. Such adjustment
de by varying the distance between the igniter
md cam-shaft /, Fig. 24. By decreasing this dis-
spark will be retarded so as to come later in the
of the engine piston; by increasing the distance,
vill be advanced, or made earlier.

HIGH-TENSION IGNITION

imp-Spark System. — With the Jump-spark, or
lion, system of igrnltion, the primary current is
by an induction coil into a secondary current of
high tension to cause a spark to jump an air gap.

Pxo. 25

system, a revolving contact timer is employed in
le snap cam k. Fig. 24. As there are no other
rts, the whole apparatus is extremely simple.

sins^le-spark, his^li- tension ignition system

•y-current supply and non-vibrator, or transformer,
strated diagrammatically in Fig. 25. One end of
lary winding a is connected to one end of the

Digitized by

Google

§7 ELECTRIC IGNITION 37

primary winding b sX pSy which may be called ihe primary-
secondary terminal of the transformer. This arrangement
reduces the number of conpecting wires necessary for join-
ing the different pieces of apparatus together. The free end
of the primary wire at ^ may be called the primary terminal
of the transformer. The free end of the secondary wire at s
is the secondary terminal of the transformer. The primary
terminal p is connected through the hand switch h to one of
the terminals of the battery A. The other terminal of the
battery is connected to the frame of the automobile at d and
thus grounded. In the timer Z", the stationary contact
piece k is supported by the insulating part /, and r is a
rotary part, or rotor, which is also grounded, being elec-
trically connected to the frame of the automobile. The
primary-secondary terminal ps \% connected to the insulated
contact piece k of the timer. One side of the condenser c is
connected to the primary-secondary terminal pSy and the
other sidQ is grounded by a connection to the frame of the
automobile at e. The secondary terminal s is connected to
the insulated electrode / of a spark plug /, and the other
electrode m of the plug is grounded through the engine and
frame of the automobile. The spark gap is between the
points of j and m^ the safety spark gap being located at g.
The hand switch h is used to open the primary circuit and
thus stop the operation of the ignition apparatus. The
dotted lines indicate the grounded return circuit through
metallic parts of the frame, engine, etc. of the automobile.

44. When the primary circuit is closed by the timer as
the end of the rotor r comes into contact with the stationary
contact piece k, current will flow from the battery Ay
through the closed switch ky to the primary terminal/, then
through the primary coil to the terminal pSy then through
the timer T'to the frame of the automobile, and finally to the
battery through the connection at d between the frame and
battery.

At the instant of the breaking of the primary circuit and
the jumping of the spark at the spark plug, the high-lension

Digitized by

Google

88 ELECTRIC IGNITION §7

current flows (assuming: a direction of flow and taking the
spark plug as the starting point) from the insulated part /
of the plug to the secondary terminal s of the transformer,
through the secondary coil of the transformer to the primary-
secondary terminal^ J, then through the primary terminal^,
through h to the battery, and through the battery to the
frame that carries it to the frame-connected, or grounded,
side m of the plug /; by then jumping the spark gap, the
current is again at the assumed starting point /.

When the primary circuit is closed, there are two paths
that the secondary current may follow between the side m of
the spark plug and the primary-secondary terminal ^j. One
path is by way of the frame to the timer and thence through
k and the connecting wire to ps^ and the other is from m
through the frame to d, then to and through the battery A
and the switch h to the primary terminal p, and then through
the primary coil to p s.

45. In the scheme shown in Fig. 25, the only connecting
wire that requires insulation to resist high electric tension
is the one between the spark plug / and the secondary
terminal s of the transformer. The switch, battery, and
timer may be located anywhere in the primary circuit, so
long as the condenser is connected directly across the break
made by the timer. If the condenser is separate from the
coil, many arrangements of the parts can be made. The
condenser and the induction coil, however, are generally
placed together inside a box. So far as electrical conditions
are concerned, the condenser is connected to the two sides k
and r of the timer. While one part of the timer T is gener-
ally referred to as being stationary, it is usually made
movable through an eighth of a revolution or so, correspond-
ing to an arc of about 45°. This is done so that the timer can
be rocked by hand, in order to make the spark come earlier
or later in the rotation of the rotor r; that is, to advance or
retard the spark relative to the motion of the engine piston.
The rocking portion comprises the insulation / and the
contact piece ^, which are rigidly connected together.

Digitized by

Google

§7

ELECTRIC IGNITION

A timer whose contacts snap apart by spring action is
sometimes used in connection with a sins;le-spark trans-
former, as stated in Arts. 17, 18, and 19.

46. A jump-spark ignition system with vibrator coil
and two batteries, as applied to a single-cylinder motor, is
conventionally illustrated in Fig. 26. At A snxdB are shown
the two batteries; at r, the case enclosing the induction coil
and condenser, and on which the coil terminals and vibrator,
or interrupter, are mounted; at A, a hand-operated switch

Fio. 26

interposed in the connections between the batteries and coil;
at {, the spark plug; and at T, the timer.

In the position of the switch blade shown, battery A is in
circuit and battery B is idle. When the switch blade is
moved over to the right, A is cut out and B is put into cir-
cuit. In the mid-position of the switch blade, both batteries
are put in parallel. Both batteries are cut out by moving
the blade either to the extreme right or to the extreme left.
The secondary terminal s of the coil is connected to the
insulated part of the spark plug /. The batteries are con-
nected to one of the two remaining terminals of the coil,

222B— 24

Digitized by

Google

Digitized by

Google

ELECTRIC IGNITION

by adding: another condenser to the arrang^ement shown in
Fig. 26.

In Fig. 27, the parts above T and h represent the ordinary
induction coil with a magnetically operated vibrator v for
interrupting the circuit. At p is shown the primary terminal;
at s, the secondary terminal; at p s, the primary-secondary
terminal of the coil; and at c z/, the usual condenser connected
across the contact points of the vibrator. The two sides of
the additional condenser ci are connected respectively to
the contact piece and the rotor of the timer 71 The batteries

PiO. 28

A and B, the hand switch k, and the spark plug / are con-
nected in as usual. The safety spark gap is shown at ^.

If the primary circuit is not broken at the vibrator, but
only at the timer) then the condenser ci acts in the same
manner as in the transformer system described in Arts. 43
and^ 44, and a spark passes at the spark plug. If the
vibrator is operating, but happens to be in position to close
the circuit at the instant it is opened at the timer, then
the condenser ci at the timer acts to break down the
arc in the timer and to produce a good spark at the spark

Digitized by

Google

ELECTRIC IGNITION

§7

plug. The condenser also acts to prevent fusing of the
timer contacts.

48« The auxiliary condenser cty Fig. 27, can be elimi-
nated and the same effects obtained by grounding the con--
denser; that is, by connecting one side of the regular coil
condenser to the frame of tlje automobile and the other
side to the vibrator, as shown in Fig. 28. The condenser is
thus placed between the primary winding of the coil on one
side and the points of the vibrator and timer on the other,
so that the condenser may be said to be in parallel with the
vibrator and timer.

Pio. 29

49. Two Spark Pla^^s Witli One Coll. — By using an
induction coil with four terminals, jump sparks can be pro-
duced at two spark plugs at the same instant. Fig. 29
shows an arrangement of apparatus for this purpose. At A
and B are shown duplicate batteries; at h, the switch; at 7",
the timer; at p and p, the primary terminals of the coil;
at s and /, the secondary terminals of the coil; and at / and r',
a pair of spark plugs connected in series with the secondary
winding of the induction coil.

Assuming a direction of flow, the high-tension current goes
from the terminal s to the insulated part / of the plug i\

Digitized by

Google

ELECTRIC IGNITION

jtimps the s:ap to m, which is connected to the metal of the
engine, passes through the engine to m'^ jumps to/, which
is insulated, and then passes to the other secondary terminal ^.
If one of the spark plugs becomes fouled or injured, so that
the current passes through it without jumping the gap, the
other plug will operate nearly the same as usual if it is still
in good order.

50. Two-Cyllnder-Engine Is: nit ion. — The jump-
spark ignition system described in Art. 49 can be applied to

Pio. 80

a two-cylinder, four-cycle engine in which the explosions
are to occur at equal intervals of time. One of the spark
plugs is placed in each cylinder. The metal of the engine
furnishes the path for the current or circuit between their
uninsulated parts.

The spark occurs in each cylinder twice as often as it
is needed— once at the proper time for igniting the charge,
and once at about the completion of the exhaust stroke of
the piston. The latter spark has no eflEect when occurring

Digitized by

Google

44 ELECTRIC IGNITION §7

5, but under some conditions of the setting of the
ly come after the fresh charge begins to enter the
In such a case» the charge is liable to be ignited
ig instant.

►tor of the timer turns at the same speed as the
, only one stationary contact is necessary for the
two-cylinder engine; if it turns at one-half the speed
ik-shaft, two contacts, half a revolution apart, are
The two contact pieces of the timer should be
connected together. This method of ignition is
d.

r methods of ignition for two-cylinder motors are
the same as for engines that have more than two

up-Cylinder Jump-Spark Igrnition With Bat-
he arrangement of an individual-coil, Jump-
Itlon system for a four-cylinder engine is shown
It differs from an arrangement for a single-
gine only in the multiplication of spark plugs, of
:oils, and of the insulated contact pieces in the
Dne of each of these parts is supplied for each of
rs. Either battery A or battery B is connected
3 switch h to similar primary terminals of all the
r, so that the primary coils are in parallel. The
ary terminals are connected one to each contact
e timer.

)e noted, the drawing shows that the wires lead-
timer contacts 3 and 4 are crossed, but they are
act at the crossing. This is done so that, if the
5 timer revolves left-handed, or counter-clockwise,
m\\ be made in the cylinders in the order 1, 2, 4, 5,
nth the requirements of an engine whose pistons
cylinders move in unison and in the opposite direc-
: of the pistons of the two middle cylinders, which
o move in unison with each other. A timer of
ere used, with four insulated contact pieces, is
ir-point timer.

Digitized by

Google

§7

ELECTRIC IGNITION

In order to keep the coils in operation in case the contacts
of the vibrator stick together, auxiliary condensers, one for
each spark coil, can be connected in as shown in Fig. 27; or,
the condensers in the coil boxes can be made to act across
both the tinier and the vibrator contacts by grounding one
side of each condenser, as explained in Art. 48.

A six-cylinder ignition system of the same nature as that
shown in Fig. 30 may be obtained by further multiplication
of the spark coils and timer contacts.

DUAIi IGNITION

52. liOTv-Tenslon Systems. — The wiring for one set
of dry cells and a generator in a low-tension ignition system
is shown in Fig. 31. When the battery is in use and con-

' Pi

PlO. 81

tact between the insulated and uninsulated electrodes of the
igniter is made, current passes from the battery a through one
blade of the switch b to the insulated electrode of the igniter af,
then through the uninsulated electrode of the igniter to the
grounded connection e, to the coil c, and back to the battery
through the other blade of the switch b. The kick coil c is
located between the frame connection, or ground, and the
switch b. In this position, the coil will be in circuit with a set
of batteries substituted for the generator / and connected
to the same switch wires as now lead to the generator.

Digitized by

Google

Digitized by VjOOQ IC

ELECTRIC IGNITION

(PART 3)

DIRECT-CDRRENT GENERATORS

PBTNCIPIiES OF OPERATION

CLASSIFICATION OF IGNITION GENERATORS

1 • The electric generators commonly employed for ignition
purposes are divided into two principal classes, namely, those
which generate a continuous, or direct, current, and those
which generate an alternating current. The former are
known as direct-current generators, dynamo-electric generators,
or simply dynamos. The latter are known as magneto-electric
generators, or simply magnetos. There are two classes of
magnetos, (1) those which generate a low-tension current for
the make-and-break type of ignition system and for delivery
to both vibrator and non-vibrator induction coils, by which
the low-tension primary current is transformed into a high-
tension current, which is led to the spark plugs by the heavily
insulated secondary wiring, and (2), those which generate
a high-tension current, embodying within themselves all the
elements necessary to the production and distribution of such
current, thereby making the use of induction coils unneces-
sary. To avoid confusion in classifying magnetos, those
which deliver a low-tension current to a step-up coil, there
to be transformed into a high-tension current, might be called
coil-type magnetos. Some magnetos of this class are driven

— PTWJIIIU BT INTtiniATIONAL TEXTBOOK OOHPANT. BNTKRBD AT BTATIONBIIB* HALL. LONDON

Digitized by

Google

2 ELECTRIC IGNITION { 8

by means of belts or by pulleys pressing against the tLywheel;
others are driven in synchronism with the crank-shaft by
means of gears whose positions have a fixed relation to the
point of maximum current production at which the spark
takes place. To distinguish the belt-driven types from the
gear-driven types of magneto, the former may be called
non-synchronous magnetos.

EliEMENTABY DIRECT-CURRENT GENERATOR

2. Whenever the number of lines of force enclosed by a
coiled conductor is changed, an electromotive force is induced

in the coil. If a conductor in
the form of a closed loop, or
\ coil, is moved in the direction
of the arrows a or 6, Fig. 1,
between the poles N and S
of a horseshoe magnet, lines of
force will be cut by the coil,
and the electromotive force
^®- ^ thereby induced will cause a

ctirrent to flow around the coil. The arrows along the sides
of the loop indicate the direction of the current when the
motion is in the direction of the small arrow a. Some mechan-
ical force is required to make the conductor cut through
the magnetic field.

3. The direction of the induced electromotive force in a
conductor is the same as the direction in which this force
would cause a current to flow if the conductor were made a
part of a closed circuit. When a conductor is moved across
a magnetic field, the induced electromotive force will act in
a direction depending on the direction of the lines of force
and the direction in which the conductor is moved. The
following rule applies:

Rule. — Pl€u:e the thumb, the forefinger, and the middle finger
of the right hand each at right angles to the other two; if the
forefinger shows the direction of the lines of force and the thumb

Digitized by

Google

§ 8 ELECTRIC IGNITION 3

shows the direction of motion of conductor, the middle finger
will show the direction of the induced electromotive force or the
resulting current (see Fig. 2).

By always keeping the three fingers at right angles to one
another, this rule may be applied to determine the direction
of an induced current in any case in which the lines of force
and the direction of motion of a conductor are at right angles
to each other; for the hand as a whole may be placed in any
position that may be necessary to make the forefinger and the
thumb point in the proper directions. For example, in Fig. 1,
if the forefinger points in the direction indicated by the small
arrowheads on the dotted lines representing the flow, or flux,
of magnetism from the north to the south pole, and the thumb
points in the direction indicated
by the arrow a, the middle finger
will point in the direction of the
induced current, the rule apply-
ing only to the conductor that is
actually cutting the magnetism
and not to the other sides of the
loop.

The intensity of the electromotive
force depends on the rate at which the conductor cuts across
the lines of force; that is, on the niunber of lines of force cut
per second.

4, Essential Parts of an Electric Generator.
The simplest of all mechanical motions is that of rotation, and
electric generators always use this principle for sweeping the
conductors through the magnetic field. There are essentially
two parts to such a machine: the field magnet, wherein is pro-
duced the necessary magnetism ; and the armature, on or near
whose surface the working conductors (those which cut the
lines of force) are arranged. These two parts are rotated
relatively to each other, it being immaterial, except for con-
venience, which is stationary and which is rotated.

5. A single conductor can seldom be made to generate a
desired voltage, so that on an armature a ntunber of con-

Digitized by

Google

4 ELECTRIC IGNITION { 8

ductors are usually connected ttp in series and in parallel, in
the same way as electric batteries, until the required voltage
and current-carrying capacity are obtained.

6. Action of Armature. — The direct-current genera-
tors used for ignition purposes generally have armatures
whose magnetic cores are in the form of a cylinder that is
either smooth or grooved lengthwise. Such an armature is
known as a drum armature. It is convenient to consider
first the nature of the current generated in an elementary
. form of drum armature with a. single closed coil, and then
the method of causing the current from a similar coil to flow
in only one direction through the portion of the circtiit
external to the armature.

An elementary drum armature with a single closed coil is
shown in Fig. 3 between the pole pieces a and b of the magnetic

field. The armature core c
is cylindrical in form;
the end view is shown.
The straight parts d and
e of the coil He along the
cylindrical surface of the
1 drum and are perpendic-
ular to the plane of the
paper on which the figure is printed. When the drum
is rotating counter-clockwise, as indicated by the feathered
arrow just beneath it, and the coil is passing through
the position shown, the straight parts d and e of the coil are
cutting through the magnetic lines of force. This induces
an electromotive force and causes an electric current to flow
through the wire of the coil in the direction indicated by the
two full arrows on the front of the coil and by the dotted arrow
on the back end. The current flows in this direction during
the time the part d is cutting through the lines from 1 to ;?,
and the part e from S to 4- The current flows through the
front of the coil in the direction from the north pole to the
south pole. While d is moving from 2 to 3 and e from 4 to 1,
no magnetic lines of force are cut; consequently, no current

Digitized by

Google

Fig. 4

§8 ELECTRIC IGNITION 5

flows through the coil. As d continues to move from 5 to 4
it cuts through the same lines and in the same direction that e
did before; at the same
time e cuts through the
lines previously cut by d
and in the same direction
as d cut them. There-
fore, when e is passing
through the position
shown in Fig. 4, the elec-
tric current will flow through the front of the coil from
e to d, as indicated by the full arrows. The direction
of flow through the front of the coil is from the north pole
toward the south pole, as before, but, inasmuch as the sides
d and e of the coil have interchanged positions, the current
flows through the wire in a direction opposite that which it
first had. An alternating current is induced in the coil by
its rotation in the magnetic field, as described.

7. The alternating current in this elementary armature
reverses its direction of flow twice during each revolution.
The reversals of current occur while the coil is passing through
its positions perpendicular to the general direction of the

magnetic flux. In
these two positions
all the magnetic lines
pass through the coil,
but it is cutting none
of them by its mo-
tion. In one of these
positions the straight
part d of the coil lies
between 1 and 4 and
the other straight
part e lies* between £
P'o- s and 3. These are the

two neutral positions of the coil, in which it is electrically
inactive while the armature is rotating.

Digitized by

Google

ELECTRIC IGNITION { 8

Fig. 5 is shown a siinple form of direct-current
having an armature on which there is a single turn
jrminating in a ring split into two parts, appr9xi-
If rings, on which the stationary brushes e, f slide as
rotates. The split ring is the commutator. The
, or segments, are insulated from each other and
haft. The brushes are so placed that, at the instant
coil passes through its neutral, inactive position and
)motive force in it reverses, the segments each break
ith one brush and slide under the other. The elec-
force generated in the conductor passing under the
5 when the core and the coil are rotating counter-
as shown by the arrow, is always toward the seg-
jr the brush e] hence, the current leaves the armature
)f brush e, which is therefore marked +, passes

77mg m Seconcti

Flo. 6

[le external circuit i?, and returns by way of brush /,
;herefore marked — .

rent through the external circuit, instead of flowing
y in opposite directions, flows in one direction only,
impulses, or pulsations, and may be represented by
le curve in Fig. 6.

aly spacing a number of coils on the armature core
ecting them to a commutator having the proper
)f segments, two coil ends to each segment, the
ipulses can be made to so overlap each other that a
Dr continuous, direct current is obtained in the
ircuit.

Digitized by

Google

§8

ELECTRIC IGNITION

DETAIIiS OF CONSTRUCTION

ARMATURE AND COMMUTATOR

9. In a solid-iron armature core rotating in a magnetic
field, there are set up in the iron of the core electromotive
forces that cause local currents, or eddy currents, to flow.

Pio. 7

Pio. 8

Fig. 7 shows how these currents circulate. The lower half
of a solid iron core is shown at C. When the core rotates,
eddy currents flow in the iron, as shown by the lines and the
arrowheads on the section. These currents cause the core
to heat, and they serve no good purpose. To prevent them,
armature cores are usually laminated, as shown in Figs. 8
and 9 (a) ; that is, they are btiilt up of disks of the proper size
punched from sheet iron.

Pio. Q

10. Fig. 9 (a) shows an armature core A for a small
ignition dynamo, and (6) shows one of the laminations, or
disks, of which the core is made. The laminations are
punched from soft sheet iron with a suitable die, so that,

Digitized by

Google

8 ELECTRIC IGNITION § 8

when assembled in the core, the slots a are formed. On the
inside of each disk is a shoulder b that slips into a notch in
the brass sleeve on which the disks are assembled. The disks
are compressed by hydraulic pressure and clamped together,
and the sleeve with the complete core is then slipped over
the shaft and keyed tightly to it.

The commutator B consists of copper segments c insulated
from each other by thin sheets, or bodies, of mica d, or a com-
position of mica and shellac called micanite; they are also
insulated from the shaft or sleeve on which the commutator
is assembled by cylinders or cones of the same composition.
The commutator also is securely keyed to the shaft.

11. The armature-core slots are insulated with smtable
paper or cloth insulation, and insulated wire is wound in the

Pig. 10

slots — a certain number of turns in each coil, the number
depending on the voltage desired and on the speed at which
the dynamo is to run. The core and commutator shown in
Fig. 9 are designed for twelve armature coils. Fig. 10 shows
one of these armatures completely woimd. This form of
armature reduces the air gap between the armature and poles
of the magnetic field. The magnetic flux is consequently
greater, and the wires cut through a stronger magnetic field
than when they are wound on a smooth core.

12. The wires leading from the armature coil to the com-
mutator segments can be connected to the segments in such
a manner as to bring the brushes in any desired position, the
only limitation being that the brushes must be diametrically
opposite each other in a bipolar (two-pole) machine. This
is accomplished by bringing the ends of the neutral coil or
coils to the segments where the brushes are to make contact.

Digitized by

Google

ELECTRIC IGNITION

FIBLB MAGNETS AND COILS

13. If a current of electricity flows through a wire wound
around the straight portions of a U-shaped bar of soft iron,
as indicated in Fig. 11, the ends

of the bar will become the

north and south poles of the

magnet. The relative directions

of winding the two coils are the

same as if the winding had

been continued along the bar

over the curve, or yoke, from

one coil to the other. By ^

providing suitable pole pieces at

the ends of an electromagnet

of this form, it can be used for

producing the magnetic field of

an electric generator. Pio. ii

14. A more compact form of field magnet is obtained by
the construction shown in Fig. 12. In this design, th^ mafgne4
poles are projections from a circular piece, instead of the ends
of a U-shaped core of the form just described. The winding

on both pole pieces is in
the same direction, so
that the poles are made
north and south. The
magnetic flux divides
equally through the two
halves of the ring, as
indicated by the feath-
ered arrows.

1 5 . Instead of using

an electromagnet, in

which part of the cur-

Fio- 12 rent that is delivered by

the armature is utilized for magnetizing the core of the

magnet, permanent magnets may be employed, as

222B— 25

Digitized by

Google

ELECTRIC IGNITION

shown in Fig. 13, for producing the field in which the
armature of the direct-current magneto-electric generator
rotaies. The armature is wotmd so that the brushes make
contact at, or near, the top and the bottom segments of the
commutator, to which the inactive coils are always con-
nected in this arrangement. When the armature is rotating,
the current flows continuously as a direct current from the
positive (-h) brush out through the external circuit R and
back to the negative (— ) brush.

16. In an electromagnet, the strength of the magrnetl-
zin^ force, or magrnetomotlTe force (abbreviated to M. F.) ,
by which the lines of force are produced, is proportional to the
strength of the current flowing through the field coil, or mag-
netizing coil, and to the number of com-
plete turns through which the current
flows. The product of the current, in
amperes, and the number of turns in the
field coil gives the magnetizing force, in
ampere-turns. A current of 10 amperes
flowing through a field coil of 20 turns
gives exactly the same magnetizing force
as 1 ampere through 200 turns, or 200
ampere-turns in each case.

17. When the number of ampere-turns on an electro-
magnet is increased, the number of lines of force, or the
magnetism, through the magnet, is increased, but not in direct
proportion. When there are few lines of force through a mag-
net, a little increase in the magnetizing force will produce a
considerable increase in magnetism; but, if the magnetizing
force is increased sufficiently, a point will be reached where
but very little further increase of magnetism can be obtained.
The magnet core is then nearly filled, or saturated, with mag-
netism. Complete saturation is never reached, but there is
a limit beyond which it is impracticable to increase the magnet-
izing force further; dynamo-electric generator field magnets
are generally run at considerably below magnetic saturation.

Digitized by

Google

§8

ELECTRIC IGNITION

18. Dynamo-electric generator fields may be separately
excited ox self-excited, according as the exciting current is
obtained from a separate source or from the dynamo itself.
There are several methods of using current from a direct-
current generator to magnetize, or excite, its own field
magnets. Self-excited dynamo-electrio generators
may be series^vound, shunt-wound, or compound-wound. In
a serles-^wound electric generator, the current that
leaves the positive brush flows through the external circuit
and then through the field coil before returning to the nega-
tive brush. The field winding is thus in series with the
external circuit — hence the name series-winding. If the cur-
rent through the external cir-
cuit, or the load, is increased
by an increase in the speed of
rotation of the engine by
which the armature is driven,
the current through the
series field winding must like-
wise increase, thus increasing
the magnetizing force and
consequently the number of
lines of force. The greater
the number of lines of force
cut by the armature coils, the
greater is the electromotive
force generated; hence, the greater the load on a series-
wotmd generator, within the limits of its capacity, the
greater is the electromotive force it will generate. Since
an increase in the speed of rotation of the armature
increases the load and consequently the electromotive force,
series-woimd generators are not used for ignition purposes on
automobiles, because it is desirable to maintain as tmiform a
voltage as possible with wide variations of engine speed.

19. The method of field excitation that probably finds
most application to direct-current ignition generators is shown
in Fig. 14, which illustrates the connections for a sliant-

Pio. 14

Digitized by

Google

12 ELECTRIC IGNITION § 8

Tvound dynamo-electric srenerator. The field magnet
is wound with an exciting coil whose ends are connected to
the brush terminals +B and —B. The external circuit R is,
of course, connected to the brush terminals. The field coil
thus forms a shunt, or by-path, for part of the current deliv-
ered by the armature. The field coil consists of a great num-
ber of turns of small insulated wire. The resistance of the
field coil is great enough to prevent a flow through it of more
than a small proportion of the amoimt of current that the
generator is designed to supply.

Whtn the external circuit R is closed, as shown, current
flows through both the external circuit and the field coil.
The amount of current flowing through each circuit is inversely
proportional to the electric resistances of the circmts. The
amount of current flowing through the armature is the sum
of the amounts in field and external circuits. If the external
circuit R is broken and its current stopped, the current
through the field coil will continue to flow as before.

When the armature stops rotating, the current through
the field coil also stops, and the field loses most of its mag-
netism. There is remaining, however, sufficient residual
magnetism to induce enough electromotive force in the
armature to cause the generator to ** pick up'* and furnish
current in the usual manner.

As the speed of rotation of the armature of a shimt-wotmd
generator increases, the electromotive force at the terminals of
the generator becomes less; this makes the field current or mag-
netizing force less, thus causing a decrease of magnetism and
a further decrease of voltage. This peculiarity makes a shtmt-
wound generator very sensitive to changes of speed. How-
ever, by proportioning the field windings so that the magnet
cores will be very highly saturated, a slight change of field cur-
rent will produce but little change in the number of lines of
force, and the change of voltage with slight changes of speed
will therefore be small.

20. A compound field winding: is a combination of a
series and a shtmt winding. The series-winding usually con-

Digitized by

Google

§ 8 ELECTRIC IGNITION 18

sists of only a few turns, the larger part of the magnetomotive
force being furnished by the shunt winding, both of which
tend, as usually connected, to increase the generated electro-
motive force as the speed of rotation increases. For opera-
ting ignition devices and especially electric lights, it is very
essential to reduce the great variation in electromotive force
dtie to the change in speed. This may be done by connecting
a series field so as to oppose a shunt field, properly propor-
tioning them, and automatically regulating, if necessary, the
ctirrent in one field winding.

21. The intensity of the electromotive force generated by
a djmamo-electric generator depends, first, on the number of

Pio. 15

coils on the armature and the number of ttfms of wire per coil,
that is, on the total number of armature turns ; second, on the
intensity of the magnetic field; and, third, on the speed at
which the armature is rotated. Increasing any one of these
three quantities, the others being unchanged, increases the
voltage of the generator.

22. A self-excited direct-current generator constructed on
the principles mentioned in Art. 18 is illustrated in Fig. 15,
which shows the complete ignition dynamo with part of tbo

Digitized by

Google

14 ELECTRIC IGNITION § 8

field frame cut away so as to show the various parts of the

a,
;ed

ing
les
ire
:he
tor
;he
;he

Fio. 17

brushes. Conducting wires connected to the binding posts e,
which are in electrical contact with the brushes, convey the
current to the external circuit.

Digitized by

Google

§ 8 ELECTRIC IGNITION 15

23. The pole pieces are removable, and are held in place
by screws /, Fig. 15, through the frame. Fig. 17 shows the
pole pieces and field coils removed from the frame. After
the coils are wotmd and insulated with wrappings of tape,
etc.> they are placed on the poles before the latter are put
into the generator. It can be seen that the poles are con-
siderably broadened at the end next to the armature.

24. The generator shown in Fig. 15 is driven by a cone-
shaped friction wheel g that bears against the rim of the
fl)rwheel. The axis of the armature is set at an angle with
the flywheel. Governor arms carrying the weights h are
attached by two pins to a split ring fastened to the armature
shaft. Bearing against this split ring is a coiled compression
spring i that forces the friction wheel g against the flywheel.
The centrifugal force of the rotating governor weights h is
transmitted to the flange of the friction wheel g by means of
the links shown, pulling the friction wheel back against the
influence of the compression spring and reducing the pressure
of the friction wheel against the flywheel.

When the speed of the armature reaches a predetermined
maximtun value, the reduction of pressure thus caused
between the friction surfaces becomes sufficient to allow the
friction wheel to slip on the flywheel. The armature speed
is thus maintained nearly constant as long as the flywheel
rotates as fast as, or faster than, is necessary to drive the
armature at the reqtdred speed. The diameter of the friction
wheel is made small enough to give the armature its maxi-
mum speed when the flywheel is rotating much slower than
the speed of an engine running by its own impulses. There
is consequently continuous slipping between the pulley and
flywheel when the engine is running.

A direct-current generator of this form for ignition use
generally is designed to give a pressure up to 10 volts, or
somewhat more, and from 10 to 12 amperes of current. For
automobiles, a direct-current generator gives its best service
when used in conjtmction with a storage battery.

Digitized by

Google

ELECTRIC IGNITION

METHOD OF INSTAIiliATION

DIRECT-CURRBNT GENERATOR AKD STORAGE BATTERT

25. Storage Battery **Floatecl on tlie Xiine." — A

direct-current generator and a storage battery, arranged to
operate in conjunction by the method known as ** floating
the battery on the line,** are shown diagranunatically in

Pio. 18

Fig. 18. In this illustration, the generator is shown at d;
the storage battery, at 6; the induction coil, at c; the high-
tension spark plug, at d; the timer, at e\ and a hand switch,
at /. In the system is included an automatic cut-out for
cutting out the armature of the generator from the main

Digitized by

Google

S 8 ELECTRIC IGNITION 17

circuit in case the speed of the generator becomes so low that
its voltage drops considerably below that of the storage
battery. With another type of the generator, shown in
Fig. 15, the automatic cut-out is incorporated as a part of
the generator. The circuit-breaker arm g, Fig. 18, of the
cut-out has a contact point that makes contact with A, to
which one terminal of the winding of the electromagnet i
is connected. At / is shown a compression spring that tends
to force the arm g away from the magnet and the contact
piece h.

When the apparatus is in operation and the generator is
producing a voltage higher than that of the storage battery,
the current from the positive (4-) brush of the generator
flows to the cut-out magnet i and then divides. Part is
shunted through a small-wire winding of nimierous turns on
the iHagnet, then through the field-magnet winding of the
generator, and back to the negative brush of the generator.
This shunt current magnetizes the core of the cut-out suffi-
ciently to draw the circuit-breaker arm g toward the core
against the resistance of the spring ;, thus bringing the con-
tact point on g against the contact piece A. The balance of
the current from the positive brush passes aroimd the magnet i,
through a coarse-wire winding of few turns to the contact
piece A, then through g to k, and out to the jtmction point /.

26. If the voltage produced by the generator at the
point / is just equal to that of the storage battery, then all
the current in the main line from the generator will pass
through / and the induction coil c, thence through the timer ^
to the frame connection, and back to the negative brush of
the generator. Under this condition, no current flows
through the storage battery in either direction; it is neither
discharging nor being charged.

In case the speed of the generator increases so as to produce
a voltage at / higher than that of the storage battery, current
will also flow through the storage battery against its electro-
motive force, thus charging the battery. The direction of
current flow through the system tmder this condition is

Digitized by

Google

18 ELECTRIC IGNITION § 8

indicated on circuits by the arrowheads. The current flowing
in the direction thus indicated in the main circuit acts together
with the shunt current to strengthen the cut-out magnet and
maintain good contact at h.

On the other hand, if the generator slows down, so that its
voltage is less than that of the storage battery, it will not
deliver any current to the system. Under this condition,
the storage battery will furnish the current for the spark coil.
If the voltage of the generator falls considerably below that
of the storage battery 6, the latter will send current back
through the armature of the generator in the direction indi-
cated by the broken arrows alongside the lines of the circuit.
This current passes in the reverse direction from that indicated
through the coarse winding of the automatic cut-out, and
opposes the magnetizing effect of the fine- wire, or shunt, coil.
The cut-out magnet thus becomes weakened to such an
extent, before the reversed current becomes great enough to
injure the generator, that the expansive action of the spring /
forces the circuit-breaker g back so as to break contact at h
and thus interrupt the main current. The generator is thus
protected against excessive current, which would be injurious
to its armature and commutator in case of slowing down or
stopping, and exhaustion of the battery is prevented.

27. When the speed of the generator again increases to
normal, the current sent through the shunt coil becomes great
enough to magnetize the core of the cut-out and draw the
arm g toward the magnet, thus again closing the main circuit
and reestablishing the normal condition of operation.

The speed of the generator can be adjusted by moving it
relatively to the flywheel against which the friction wheel
presses. By thus regulating the speed of the generator so
that its voltage is about that of the battery when fully charged,
current will be delivered to keep it always well charged after
the generator has been running for some time. The voltage
of the system is practically that of the battery.

The advantage of this system is that a constant electric
pressure is always at hand. This is a convenient feature for

Digitized by

Google

§ 8 ELECTRIC IGNITION 19

starting the engine and can also be utilized for electric
lighting. The lights on the vehicle can be kept burning
whether the engine is running or not. The length of time,
that the lights can be burned when the generator is not
running depends, of course on the current required for them
and on the capacity of the battery.

MAGNBTO-BLECTBIC GENERATORS

PBINCIPI-ES OP OPERATION

THEORY OF THE MAGNETO GENERATOR

28. Tmw of Electromasnetic Induction. — ^The action
of the magneto generator depends directly on a law of elec-
tromagnetic induction. One way of stating this law is, that
if the number of lines of force passing through a coil of wire
is varied, an electromotive force will be set up in the coil,
the intensity of which will depend on the rate at which the
lines are varied, and the direction of which will depend on
the direction of the lines and whether their number is being
increased or diminished. One way of varjdng the number
of lines through a coil is to pass a variable current through
another coil woimd on the same core, as in an ordinary induc-
tion coil. Any changes in the strength of the current in the
primary winding cause corresponding changes in the strength
of the magnetic field, which, by the law just stated, produce
electromotive forces in the secondary coil. Another way of
changing the number of lines of force passing through a coil
is to move an electromagnet or a permanent magnet in the
vicinity of the coil. Still another way is to move the coil
with respect to the magnet; and it is by this method that the
magneto generator is made to produce electromotive forces,
and, therefore, when the circtiit is closed, corresponding
currents.

Digitized by

Google

20 ELECTRIC IGNITION § 8

29. Indnction In BeTOlTlng lioop. — In Fig. 19 is

^ be revolved about a
set of three permanent
indicated by the hori-
rom the north pole to
onception of their flow,
s :»: ^ in the direction of
ly stdtable means.
)osition, it will lie in a
i therefore will include
none of the lines.
As it is turned into
the position shown
by the full lines, it
will include more
and more of the lines
of force, and there-
fore will have an
electromotive force
and a corresponding
cturent set up in it
in the direction of the
arrows a. When the
coil reaches its verti-
cal position, it will
include all the lines
umber of lines through
but will be decreasing.
; through the coil will
change after passing the vertical position, and the flow of cur-
rent will then be indicated by the direction of the arrows 6.

30. If the coil is revolving at a constant speed, the rate
of change of the lines of force through the coil will be very
slow as it approaches and recedes from its vertical position,
being zero when the plane of the coil is at right angles to the
direction of the lines of force, and therefore the induced
electromotive force here is zero. As the coil approaches its

Digitized by

Google

§ 8 ELECTRIC IGNITION 21

horizontal position, the rate at which the number of lines
through it is changing will increase, and the electromotive
force will therefore increase correspondingly, although the
actual number is more and more rapidly being reduced to
zero. When the coil reaches its horizontal position, the
electromotive force in it will be a maximum because the rate
of change of the lines of force is a maximum, although the
number threading through the coil is zero. At that point,
the number of lines passing through the coil again begins to
increase; this would produce a change in the direction of the
electromotive force were it not for the fact that the direction
of the lines through the coil relative to the plane of the coil
also changes. The electromotive force is therefore at a
maximum at the horizontal position of the coil, because the

'0n€ Cye/0

• Off^CycM'

Fio. 20

rate of change of the lines through the coil at that point is a
maximum. As the coil again approaches its vertical position,
the rate of change becomes less and less, and as it reaches
that position, no change takes place, and the electromotive
force therefore becomes zero. From this point on to the
starting point, the number of lines decreases, therefore, again
producing an electromotive force in the opposite direction,
which becomes a maximum as the horizontal position is
reached.

31. Graphic Representation of Magrneto Current.

The flow of the current to and fro in the coil may be repre-
sented by a curve, such as is shown in Fig. 20, the distances
above or below the horizontal axis a i being made proportional

Digitized by

Google

22 ELECTRIC IGNITION § 8

to the instantaneous values of the current or the electro-
motive force, whichever the curve is considered to represent.
Assuming the curve in Fig. 20 to be an electromotive force
curve, the point a on it corresponds to the vertical position
of the loop in Fig. 19. At this point no electromotive force
is set up in the loop, and therefore the point a is on the hori-
zontal axis of the curve. As the loop rotates on its axis, the
electromotive force gradually increases until it lies in a
horizontal plane, where the electromotive force is a maximtmi
because the lines of force are then being cut by the loop at a
maximum rate. This condition is represented by the point b
on the curve where the electromotive force is a maximum.
From the horizontal position of the loop in Fig. 19, the elec-
tromotive force remains in the same direction, but decreases
until the coil again reaches a vertical position, when it
becomes zero; this is represented by the point c on the curve.
At this point, the direction of the electromotive force changes
and the curve passes below the horizontal line; and during
the next half revolution of the loop, while approaching the
second horizontal position, the changes are of the same
nature, but in an opposite direction, the electromotive force
reaching a maximum in this direction at the point d corre-
sponding to the second horizontal position of the loop, and
again decreasing to zero, as shown at e, when the loop is at
the same vertical position from which it started. A complete
revolution of the coil, therefore, produces one complete cycle
of changes in the electromotive force and in the current, as
represented by the curve ab cde, the curve efghi repre-
senting a second similar cycle of changes in the electromotive
force. While in this case the electric cycle is completed
during one revolution of the armature. Some magnetos are
so constructed that the complete electric cycle is passed
through in less than one revolution of the armature.

32. The electromotive force generated in the coil is alter-
nating and if the coil is made a part of a closed circuit an
alternating current will flow through the circuit. If the
electromotive force generated while the coil is passing under

Digitized by

Google

§ 8 ELECTRIC IGNITION 23

one pole is called positive ^ that generated while passing under
the other pole will be negative, and the loops of the curve in
Fig. 20 are made to indicate the change in direction by their
reversed position with reference to the zero line.

33. Current Trequency. — The frequency of an

alternating current is generally measured in the number of
its electric cycles per second. A rapidly alternating current
has high frequency; a slowly alternating current has low
frequency.

ELEMENTARY MAGNETO GENERATOR

34. An elementary form of alternating-current magneto-
electric generator is illustrated in Fig. 21, which shows the
armature core and pole pieces N and S of permanent magnets

Pig. 21

to which they are attached, and also a coil consisting of two
active conductors c and d connected in series and having their
free ends joined to two metal collector rings, or slip rings,
g and A. As the armature core and the coil rotate, con-
ductor c is passing under a north pole at the same time that
conductor d is passing under a south pole, so that the elec-
tromotive forces generated in the two conductors, though
opposite in direction with reference to the poles, are the same

Digitized by

Google

24 ELECTRIC IGNITION § 8

in direction with reference to the coil; hence, the electro-
motive force between the collector rings is the sum of the
forces generated in conductors c and d. Stationary copper
strips e and /, called brashes , rub on the collector rings as they
rotate with the armature, and an alternating current flows
through the brushes and the external circuit R. The arrows
along the conductors and the external circuit show the direc-
tion of the current at the instant represented. When the
armature has rotated until the conductors c and d have
exchanged positions, the direction of the current through the
coil and the external circuit will be reversed.

35. Instead of having but a single turn of wire, as in the
loop shown in Fig. 21, a coil consisting of a. great number of
turns is used in practice, so that the electromotive force
generated in each turn may be added to that of all the others.
Furthermore, in order that the greatest possible number of
lines of force may flow between the magnet poles and through
the coil, the coil is wound on a core of soft iron adapted to fit
closely between curved polar extensions, or pole pieces, of iron
secured to the poles of the permanent magnets.

DETAILS OF CONSTRUCTION

ARMATURE CORK AND WINDING

36. The magneto-electric, or alternating-current, gene-
rators used for ignition ptu-poses usually consist of an arma-
ture core a. Fig. 22, having wound thereon a single coil of many
turns of fine instdated wire, and arranged to rotate between
the poles b of one or more U-shaped permanent magnets iV, S.
The armature core is usually made with a cross-section resem-
bling the letter H, ^ shown by the end view in Fig. 22 and
the perspective view in Fig. 23 (a), and may be soUd iron or
laminated, the best ones being laminated. One end of the
armature coil is usually connected to the armature shaft,
or spindle, and the other to an insulated pin or ring. The

Digitized by

Google

ELECTRIC IGNITION

collecting brushes are arranged to rub against the shaft and
the insulated pin or ring, respectively. The shaft is some-
times run directly through the core, but on some modem
magnetos the shaft is in two parts, each bolted to an end plate,
which is attached to end projections on the armature core,
leaving between the plate and the body of the core a space
for wire.

Fig. 23 (6) shows such a core completely wound. The coil
is wound Solid, as shown at b in the sectional end view.
Fig. 23 (c), instead of being separated into two parts, as
would be necessary if the shaft extended through.

Fig. 23 (c) also shows, by the dotted
lines, how the magnetic flux passes through
the core and the coil when in the position
shown. When the armature has turned
one-fourth revolution, so that the iron
projections c are opposite the neutral
spaces between the poles, almost no mag-
netism passes through the coil. As the
core rotates, it thus cuts the magnetism
in and out and generates an alternating
current.

37. In magneto generators for auto-
mobile use, the slip ring is frequently Pio. 22
eliminated by making the spindle hollow and carrying, one
of the armature wires out through the hole to an
instilated contact piece at the end of the spindle. This
contact piece may be only an insulated pin against whose
ends the part substituted for the brush bears. In some
cases, the brush that would bear against the spindle is not
used, but the metallic contact between the spindle and its
bearings is depended on for making electric connection
between the spindle and the frame of the generator. This
arrangement is not always satisfactory, however, because the
film of oil between the spindle and its bearing is some-
times thick enough to act as an insulator and thus prevent
electric connection between them.

—26

Digitized by

Google

26 ELECTRIC IGNITION § 8

38. In Fig. 23 (6), one end of the coil a is carried out
through the hollow spindle b to the insulated piece c, and the
other end is fastened to the core, or head-piece, by the screw d.
The sharp edges of the parts e and / throw off the oil as the
armature rotates and cause it to drip off when the armature

(b)

(d)

Fio. 23

is not rotating, so that the oil will not get into the armature
winding. In Fig. 23 (d), one end of the armature winding a
is connected to the insulated slip ring fc, and the other end is
connected to the armature core and spindle. The deep
flange c and the shallow flange d prevent oil from the bearings

Digitized by

Google

S 8 ELECTRIC IGNITION 27

from reaching the winding, and the flange c also insulates the
slip ring h from the ball bearing. The end pieces e and / are
made of some non-magnetic material, generally brass, bronze,
or alimiinimi alloy, so that they will not form a magnetic
path between the magnetic poles and cause the mag-
netic flux to deviate from the desired path through
the core around which the coil is woimd. The spindle
is usually made of steel. The non-magnetic heads magnetic-
ally insulate the spindles from the armature core. The cir-
cumferential bands h around the armature hold the wires of
the coil in place, so that they will not fly outwards when the
armature is rotating. They also are made of non-magnetic
material. Each armature shows at the left-hand end a spur
gear g by which it is driven. The bearings in Fig. 23 (6) are
of the plain cylindrical type,
with the spindle forming the
journal, which has sliding con-
tact with its bearings; the
armature shown in Fig. 23 {d),
however, has ball bearings.

39. When the armature
core is made of one solid piece ^'® ^4

of wrought iron or soft steel, electric currents of considerable
magnitude are induced in it as it rotates between the magnet
poles. These currents flow from one part of the core to
another part, and on account of the nature of their flow are
called eddy currents. They are objectionable on account
of heating the armature and reducing the electric pressure
that is induced in the armature coil. In order to eliminate
the eddy currents as far as possible, the core is made up of
thin sheet-metal punchings or stampings, as shown in Fig. 24.
The metal sheets from which the pieces are punched or stamped
are about the thickness of thin stovepipe iron or even thinner.
Iron and steel of the softest and purest quality are used in the
best construction. The stampings are placed side by side to
build up the core. They are sometimes separated from each
other by thin sheets of paper, so as not to come into close

Digitized by

Google

28 ELECTRIC IGNITION § 8

metallic contact and thus form electric connection. In other

f iron on the surface is depended
^ from each other electrically.
)ressed together and fastened by

ng. — The electric pressure, or

B^enerator shown in Fig. 21 can

lature winding two turns aroimd

the core instead of one, if the

two turns are in series. The

turns are in series when, in

winding the coil, the wire is

wrapped twice around the

core instead of once, and the

two ends are connected as

before. The series-winding is

the same as wrapping a string

twice around a package. If

the number of turns in series

is increased still more, the volt-

age that the armature will

develop will be correspondingly

increased, provided all' other

conditions remain the same

as before. In actual practice,

for this form of winding, the

arly proportional to the number

B armature core. An armature

(d) is called a sliuttle-i?voand

FIELD MAGNETS

41. Fig. 25 shows the magnets, or field, used with arma-
tures of the form illustrated in Fig. 23 (6). The field is made
up of three magnets placed side by side. Each magnet is
double, or compound, consisting of one magnet a fitted over
another b. Iron or soft-steel pole pieces c bored to suit the

Digitized by

Google

§ 8 ELECTRIC IGNITION 29

armature are attached to the magnets. The magnets are
fastened firmly to a non-magnetic plate d that forms the base
of the generator. This base may be of brass, wood, vulcanized
wood fiber, or some other suitable material.

The thinner bar steel that can be used by making each
magnet in two component parts can be given a greater degree
of hardness than the thicker material that would be required
if each magnet were made in one piece. The harder the
material, the better it retains its magnetism. Also, the
thinner bar of hard steel is more easily magnetized than the
thicker bar. On the whole, a stronger magnetic field and
more permanent magnets are obtained by this method of
making up the field.

liOW-TENSION MAGNETOS

42. When a magneto generator delivers a current of low
voltage, such as is used for contact ignition or for the primary
winding of a spark coil, it is generally known as a lo^w-ten-

Pio. 26

slon mAgneto, Under this classification, therefore, any mag-
neto with which it is necessary to use a separate vibrator or
non-vibrator coil to produce a high-tension current is of the
low-tension type.

Digitized by

Google

30 ELECTRIC IGNITION § 8

Inasmuch as the basic principle tmderlying the operation
of low-tension magnetos is the same for all types, I'egardless
of variation in details of construction and application of prin-
ciple, no attempt will be made to describe in detail the special
characteristics of the many domestic and foreign magneto-
electric generators at present in use. A description of some
of the common types of machines will suffice to give a general
idea of the characteristics of all.

One type of low-tension alternating-current magneto is
shown in cross-section and longitudinal section in Fig. 26.
For a four-cylinder four-cycle engine, it is driven by gearing
at the speed of the engine, the gears being set so that the
range of the spark timer coincides with the effective range
of the magneto current. The armature positions deter-
mining the latter are marked on the magneto, and it is
unnecessary to change the angular relation of the armature
to the engine crank-shaft when the spark is advanced or
retarded. The principal features of construction are as
follows:

The permanent magnets a have pole pieces b fastened to
them by screws. The armature core c is wound with double
silk-covered magneto wire, and the ends of the core are
screwed to hard brass disks d, into which the two shaft
sections e are screwed and riveted. The object of this con-
struction is to make a neater and more compact winding of
the armature than would be possible if the shaft passed
through the core. One of the terminals of the armature
winding is insulated, and the other is grounded on the frame
of the generator. The insulated terminal of the coil is con-
nected to a hardened-steel bolt /, insulated by a mica bushing g
through the armature shaft, and the current is taken off by
a hardened-steel contact pin h in the brass mounting i, carried
by the hard-rubber tube / screwed over the end of the bearing.
From i, a flexible connector leads to the binding post k. The
entire magneto is provided with an aluminum housing, com-
prising a sheet cover / and cast end plates m and n, together
with top and bottom plates o and p, and a cap q to exclude
dust. The shaft is lubricated by oilers r.

Digitized by

Google

ELECTRIC IGNITION

43, A magneto of this type can be used either for low-
tension contact ignition or for supplying current to a coil of
the transformer, or non- vibrator, type for high-tension ignition.
For low-tension igni-
tion, no kick coil is
required, because the
magneto armature
has sufficient self-in-
duction to produce a
considerable spark
when the contact
points separate inside
the engine cylinder.
For high-tension ig-
nition, this magneto ^Q. 27

can be used with a suitable timer and either a transformer
type of coil without a vibrator for interrupting the primary
current, or with an induction coil having a magnetically
operated vibrator for interrupting the current. The arma-
ture winding must be suited to the service required. The
binding post k is used for connecting the magneto to the
other apparatus of the ignition system.

44. Inductor Type of Magrneto. — An alternating-
current magneto of the inductor type, in which the armature
winding is stationary instead of rotative with the mechanically

driven rotor, or armature core, is
shown diagrammatically in side and
end elevations in Fig. 27. The rotor,

, or armature core, as shown in Fig. 28,

consists of two arms ab and c d,
made up of thin sheet-iron punchings,
placed at right angles to each other;
they are connected by a short cylin-
drical neck whose axis is coincident

with that of the spindle on which the rotor turns when in place.
The position of the rotor in relation to the magnetic poles

is shown in Fig. 27. The coil k is placed around the cylin-

Pio. 28

Digitized by

Google

ELECTRIC IGNITION

§8

drical portion of the rotor. The coil is wound spirally, like
a clock spring. The wire used is a flat ribbon of copper,
resembling a clock spring in cross-section, and is, of course,
instilated. This spiral armature coil is held stationary with
regard to the magnets. Its terminals are led out to stationary
binding posts or other suitable devices for making connection
with an external circuit.

45. The action of the magneto depends on var3ring the
number of lines of magnetic force through the armature coil.
The manner in which this is accomplished can be seen by

Pio. 29

referring to Fig. 29. In the position shown in Fig. 27, the
only magnetic flux that takes place is through the upper end
of the arm c of the rotor. There is no flux through the cylin-
drical portion that forms the core of the winding.

When the rotor has moved to the position shown in
Fig. 29 (a), the magnetic flux is from N to a, then through
the cylindrical neck to the arm c and out through c to S.
The flux is from the front toward the back end of the rotor
when it is in the position (a). With the rotor in the position
(6), all the magnetic flux that takes place is from N through
the upper end of a to S. On reaching position {c), the flux

Digitized b^

Google

§ 8 ELECTRIC IGNITION 33

is from N through d to the cylindrical neck, then up toward
the front arm a and through a to 5. In this case, the flux
through the cylindrical neck is from the rear bar c d toward
the front bar a fc, instead of from the front bar toward the
rear one, as in (a). On reaching its position (d), the flux
through the cylindrical neck has again entirely ceased.

It will be seen that while the rotor has moved through one-
half revolution from the position shown by Fig. 27, to the
position shown at (d), in Fig. 29, the magnetic flux through the
center of the core of the winding k has been twice raised from
zero to the maximum value and dropped down to zero again.
Therefore, for a complete revolution of the rotor there are
four maximum values of magnetic flux. There are also four
times at which the electric current reaches its maximtun in
the stationary winding during one revolution of the rotor.

46. What is known as the K-W magrneto is con-
structed on the principle just described. To facilitate
assembling and separating
the parts, one of the rotor
bars is made removable.
The machine is made to
run in either direction and
in any position, the oil cups
being arranged accord-
ingly. For jump-s park
ignition, it should be run
at a speed at least three ^^' ^

times that of the engine, so that under normal working
conditions it will have a speed of from 2,500 to 3,500
revolutions per minute. With these speed ratios, sufficient
current is generated on a quarter turn of the starting
crank to permit of starting the engine, thus obviating
the use of batteries for starting purposes. Because of the
impedance, or inductive resistance, of the coil and circuit, the
K-W magneto is self-reguiating, so that, while at low speed,
it will generate enough current to start the engine with a
quarter turn of the starting crank; neither it nor the coil will

Digitized by

Google

Digitized by

Google

f 8 ELECTRIC IGNITION 35

be injtired when the engine is speeded up, no matter how fast
it *niay be run. Four powerftd sine waves of alternating
current are produced per revolution of the magneto, giving
sufficient power to operate the vibrator of the coil the instant
that the circuit is closed by the timer.

47. The stationary armature winding and the soft-iron
rotor of the Bemy magrnetOy which operates on the prin-
ciple just described, is shown in Fig. 30. In this design, the
rotor is placed between the magnetic poles in a manner
similar to that of the shuttle-wotmd . armature already
described. There is, of course, only one complete electric
cycle per revolution, with its two maximum values of current.

Current is generated by means of a solid steel shaft a.
Fig. 31 (6), on which are mounted two steel inductor wings b
that revolve between the pole pieces of the three permanent
double U magnets c. Between the inductor wings is placed
a stationary winding or coil d of coarse magnet wire within
which the current is generated. From this winding the cur-
rent flows to the transformer, or non-vibrator, coil on the
dashboard and thence back to the hard-rubber distributor e
on the face of the magneto. Just above the steel inductor
shaft a is the distributor shaft /, which is driven by the
inductor shaft through the pinion g and gear h. On the
extreme end of the distributor shaft / is a fan-shaped brass
segment t. Fig. 31 (a), that receives the high-tension current
from the coil through the high-tension cable connected
thereto. This segment revolves, passing the terminals of the
wires leading to the spark plugs.

The circuit-breaking mechanism is a double-lobed cam j
located on the end of the inductor shaft. The inductor shaft
travels at crank-shaft speed, and the double cam interrupts
the circtiit twice, therefore making two sparks for every
revolution of a four-cycle four-cylinder engine. The dis-
tributor shaft travels just half as fast as the inductor shaft;
therefore, there is one spark for every quarter turn of the
distributor shaft, or one spark as the brass segment passes
each terminal of the four wires found on a four-cylinder

Digitized by

Google

36 ELECTRIC IGNITION $ 8

engine. In a six-cylinder engine, the magneto is geared to
run half again as fast as the crank-shaft. With relation to
the movement of the pistons the timing is thus fixed mechanic-
ally, a powerful, hot spark being produced in the cylinder
under compression at exactly the right instant, assuring
maximum engine power. The spark is advanced or retarded
by rocking the circuit-breaking cam housing k from right to
left, a timing range of 60^ being provided.

As dry batteries may be wired through the transformer coil,
one type of dual ignition can be had with a single set of spark
plugs. When batteries are used, the engine may be started
on the spark without cranking, a push button being provided
on the coil, so that by merely pushing it inwards a hot spark *
is delivered in the cylinder under compression.

liOW-TBNSION MAGNETO-IGNITION SYSTEMS

CUL881F1CATION AND ARRANGEMENT

48. There are several systems or methods of utilizing
the low-tension current primarily generated by a magneto.
The following are some of the principal ways of applying the
current generated in the low-tension winding of the magneto
armature, a condenser always being used to aid in producing
sudden variations of the primary current:

1. Interrupted primary current.

2. Short-circuited primary current.

3. Interrupted short circuit of primary current.

4. Condenser charge-and-discharge system.

49. Interrupted Primary Magrneto Current.— One

of the fundamental methods of applying the current from a
magneto for jump-spark ignition is shown in Fig. 32. The
armature a of the magneto is wound with only one coil of
several turns. One end of the winding b is connected to the
frame of the machine, and the other end is led through the
hand switch c to the primary terminal d of the spark coil.

Digitized by

Google

§8

ELECTRIC IGNITION

The primary-secondary terminal e of the spark coil is con-
nected to the instilated stationary contact piece / of the timer.
The arm g of the timer is connected to the frame of the
machine at the hinged end. The rotor h of the timer is shown
in the form of a two-lobed cam. The lobes of the cam lift
the arm g to break the primary circuit at the instant ignition
is required. One side of the condenser * is connected to the
wire joining e to the timer, and the other side is connected
to the frame, so that it is in parallel with the break in the
circuit made as the timer contacts separate.

The discharge of the condenser passes through the trans-

Fio. 32

former primary, the switch c, the magneto armature winding &,
and thence to the frame and the other side of the condenser.
The spark plug / is connected to the high-tension terminal k
of the transformer coil in the usual manner. If the timer
closes the circuit when the armature has made about a quarter
revolution from the position shown, the increase of current in
the transformer coil will be gradual compared with its
cessation, and no spark will be formed at the time of closing
the circuit.

60. If both the armature and the two-lobed timer rotate
at the same speed, the system will give a spark every half

Digitized by

Google

ELECTRIC IGNITION

l»

revolution; that is, of course, two sparks every revolution.
When the speed is the same as that of the crank-shaft of a
four-cylinder, four-cycle, single-acting engine, the spark will
be produced with the necessary frequency for the four spark
plugs.

A high-tension distributor is, of course, required when there
is only one transformer coil and more than one engine cylinder.

If the cam is filled in on one side, as indicated by the dotted
line, there will be only one spark produced every revolution.
If a cam filled in on one side, as just mentioned, rotates at
half the speed of the magneto armature, there wiU be a spark
produced every second revolution of the armature. With

Pio. 33

four timers of the latter nature, each breaking the circuit
every two revolutions of the armature, and four corresponding
individual transformers, the spark at the plugs can be pro-
duced with the required frequency for four spark plugs in a
four-cylinder four-cycle engine when the magneto armature
and engine crank-shaft rotate at the same speed.

The timer cam h can be fastened rigidly to the spindle of
the magneto without insulation, and the contact arm g of
the timer can be rotatively moimted on the part electrically
connected with the spindle. As shown, the arm g is electrically
connected to the frame of the machine, but the contact piece /

Digitized by

Google

§8

ELECTRIC IGNITION

which can be carried on the same part as g, mounted con-
centric with the rotor h, must be insulated. The timer can
be rocked in the usual manner for varying the time of ignition.

51. Sliopt-Ctrcuited Primary "Magneto Current.

With the arrangement shown in Fig. 33, all the armature
current passes through the primary winding of the transformer
when the arm g of the timer is not in contact with its insu-
lated contact piece /. The rotor h of the timer brings the
arm g into contact with / at the instant that a spark is to be
formed for ignition. The closed timer thus short-circtiits
the transformer by furnishing another path of less resistance

Pig. 34

for the current of the magneto to travel through. The new
path is through the armature of the magneto to the contact
piece /, and then through g to the frame of the machine and
the opposite end of the armature winding. This latter circuit
offers far less resistance than the circuit through the trans-
former; nearly all the current therefore travels through the
timer on the short circuit when the timer is closed. The
sudden drop of current in the transformer primary at the
instant that the timer closes the circuit induces a spark at
the plug.

Digitized by

Google

ELECTRIC IGNITION

The condenser acts in practically the same manner as
indicated in the preceding examples, but it can be omitted
without great injury to the contact points of the timer or
great modification of the strength of the spark.

The hand switch c is kept open during the operation of the
system. In order to stop sparking, the hand switch is closed.
The magneto armature is then practically short-circuited.
The armature of the magneto is wound and otherwise so
constructed that it will run on short circuit without injury
to itself or other parts of the apparatus.

Fio. 35

52. Interrupted Short Circuit of Primary Mas^i^eto
Current. — An ignition system depending for its operation
on an interrupted short circuit of the primary magneto current
is shown in Fig. 34. In this figure the same reference letters
that are used in Fig. 33 have been applied to similar parts.
The contact points of the timer are left together tmtil the
primary current of the armature attains its maximum value.
On accoimt of the low resistance of the short circuit through
the timer, nearly all the primary current passes through it.
Only a small amotmt of the current flows by way of the path

Digitized by

Google

i 8 ELECTRIC IGNITION 41

through the transformer, because the latter has a far higher
resistance in its primary winding than that of the short circuit
through the timer.

When the short ciroiit is broken by the mechanical action
of the timer, there is a sudden increase of current through the
primary winding of the transformer. This sudden increase
acts in the usual manner to induce a high tension in the
secondary coil, so that a spark will jtunp at the plug. The
condenser must, of course, be correctly proportioned in order
to obtain good results.

53. Condenser Cliarse-ancl-Discliarsre Bysteni.

Another system of applying low-tension magneto current for
jtunp-spark ignition is illustrated diagrammatically in Fig. 36.
In this system, the electricity generated by the magneto
is first stored in a condenser i without passing any current
through the transformer; then, after the primary ciroiit of
the magneto is open, the condenser is discharged through the
primary coil of the transformer at the instant a spark is
desired.

The magneto winding is connected to the insulated contact
piece c of the primary circuit-breaker. The rotor d lifts the
circuit-breaker arm e at the time the magneto is giving its
full, or nearly full, current strength. The condenser * is thus
electrically charged. The timer arm / is not in contact with
the insulated contact piece g during the time of charging the
condenser. The rotor h lifts the timer arm / to make contact
with g aind thus closes the condenser circuit through the
primary winding / of the transformer, whose high-tension
terminal is at k. At the instant contact is made at g, the
condenser discharges its current through the transformer,
and a spark is induced at the spark plug /. By this arrange-
ment, the magneto circuit is connected to the condenser, and
the latter is charged by the magneto always at the same
time without regard to whether the spark at the plug is made
early or late by rocking the timer. The electric circuit from
the magneto is never closed so as to allow a circulating flow
of electricity.

222B— 27

Digitized by

Google

42 ELECTRIC IGNITION § 8

As mentioned, the timer can be so mounted as to admit
of rocking it for varying the time of ignition. The circuit-
breaker can be mounted stationary, so as to be independent
of the rocking of the timer.

DUAIi IGNITION SYSTEMS

54, A low-tension magneto of the condenser charge-and-
discharge type for jump-spark ignition is illustrated in Fig. 36.
The armature has a laminated core a and rotates on ball
bearings. On the armature shaft is mounted the regular

Fig. 38

mechanically operated timer b of the interrupter type, which
has a two-lobed cam for making and breaking the primary
circuit.

A second shaft c is run by the pinion and gear d and e at
one-half the speed of the armature, and carries a four-lobed
primary contact maker / and also the secondary* current
distributor g. Fig. 37 shows the wiring connections. One
end of the armature winding is grounded on the core, as
usual, and the other is connected to the mechanically operated
interrupter 6, and through the wire h to the primary of the
induction coil i. The other terminal of the primary is con-

Digitized by

Google

J 8 ELECTRIC IGNITION 43

nected to the coil vibrator and also to the condenser /. A
switch k has its blade connected with the other condenser
terminal, and has the three contacts connected, respectively,
to the vibrator / and the positive and negative terminals of
the battery w, as shown. The positive terminal of the battery
is grounded.

55. When the switch is in the position shown by the dotted
lines, and the circuit is closed by the primary interrupter 6,
a charge of electricity

passes through the wire A
and primary winding
of the coil i into the
condenser ;. As soon
as the condenser is
charged, which takes
but an instant, no fur-
ther current can flow,
because there is no
closed circuit connected
to the armature wind-
ing. The contact is then
broken, leaving the con-
denser charged, and at
the proper moment for
the spark a contact is
made by the timer /,
thus grounding the
wire h and permitting the
condenser to discharge
itself through the pri-
mary winding of the Fio. 37
coil t, the flow being now in the opposite direction to that of
the momentary charging current. The discharge of the con-
denser is so sudden as to induce a very high momentary
voltage in the secondary winding of the coil.

56. As one end of the secondary winding of the induction
coil is connected to the primary winding, the secondary wind-

Digitized by

Google

44 ELECTRIC IGNITION § 8

ing is grounded while the timer / is making contact. The
other end of the secondary winding is connected by the
cable n to the central terminal o of the high-tension dis-
tributor g, whose arm p. Fig. 36, is secured to the rotating
hard-rubber disk q attached to the shaft c. Fotir fixed ter-
minals, motmted in the same hard-rubber piece' r that holds
the central terminal, distribute the current to the spark plugs.
As the end of the arm p is widened, no advance is required in
the distributor, and hence the timer /, Fig. 37, is the only
member moved to change the spark time, the condenser
simply remaining charged, between the moments of contact,
by b and /, respectively.

As already stated, the battery furnishes current for start-
ing, the switch k then being turned to the position shown
in ftill lines in the diagram. The magneto is thereby dis-
connected, and the battery current goes through the engine
frame, contact maker /, wire A, primary winding of the coil,
vibrator /, and the switch. The current can also go by way of
the armature winding and interrupter b\ but, if the vibrator is
adjusted for the current reaching the coil by the more direct
route, it will not respond to the weaker current. When the
engine reaches normal speed, the switch is thrown over by
the operator. The switch is of special design, and is very
highly insulated to protect the operator from shocks. It is
claimed that this magneto will produce a 3-inch spark in the
open air at 600 revolutions per minute, and a f-inch spark at
50 revolutions per minute. As only a single spark is pro-
duced, it can be timed with perfect accuracy.

As illustrated, the magneto is suitable for a four-cylinder
four-cycle engine when its armature rotates at the same speed
as the crank-shaft of the engine. For a six-cylinder four-
cycle engine, the armature must make three revolutions for
every two revolutions of the engine crank-shaft.

Digitized by

Google

S 8 ELECTRIC IGNITION 45

HIGH-TENSION MAGNETOS

67. With reference to electric ignition, a liiflrb.-ten-
sion mafirnetOy strictly speaking, is a magneto that delivers
electric current of suflBciently high voltage, or tension, to
jump the gap of a jump-spark plug tmder the usual con-
ditions of operation, the high-tension current being produced
and delivered without using any auxiliary coils or wiring
separate from the magneto. The high-tension magneto per-
forms all the ftmctions of an electric generator, a timer, a
spark coil, and, for the usual case of four or more cylinders,
a distributor. It is really the embodiment of all these
individual parts in a single piece of apparatus.

MAGNETO WITH SINGLE ARMATURE WINDING

58* The Hess-Brig^ht liig^li-teiisioii meignetOy shown
in sectional elevation in Fig. 38, operates on an interrupted
short-circuit system substantially the same as that described
in Art. 52 in connection with Fig. 34. The magneto has a
rotary armature with a single winding, generating a low-
tension current that passes through the primary ^winding of
a transformer that forms an integral part of the magneto.
The primary current generated in the armature a flows
through the insulated primary terminal b to the bridge c
by means of an interposed carbon button d that is held in
easy contact with the end of terminal fe by a light stirrup
spring. One of the bolts e supporting the bridge c delivers
the current to branching circuits in the large, hard-rubber
block /. With the interrupter closed, current flows through
the fixed platinum-ended terminal g to the platinum-ended
interrupter lever A, to the magneto framing, and then to the
ground. With the interrupter open, the primary current is
conveyed to the transformer spool * through spool terminal /.
This spool is encased in hard rubber and is further protected
by its location between the permanent magnets. The pri-
mary current leaves the transformer by way of terminal k

Digitized by

Google

Digitized by

Google

$ 8 ELECTRIC IGNITION 47

which is in circuit with the grotmd through the frame of the
magneto. The terminal screws ; and k are secured by double
locknuts.

The secondary, or high-tension, current leaves the trans-
former by way of screw terminal /, and is carried by the
spring blade m to the distributor «, whose carbon brush o
delivers it in turn to the four terminal segments pi, p^, p^,
and p^ that are sunk into the large hard-rubber block /; these
segments are connnected electrically to the usual terminal
plugs q to which the spark-plug cables are connected. The
condenser r is located between the armature and the trans-
former spool. The lever s for timing the ignition j)rojects
from the side of the magneto near the rear, or engine, end.
The distributor, interrupter, and various other front parts
are enclosed by the large, solid hard-rubber cover /. Pushing
the detent spring levers u to one side permits the removal of
the cover and also uncovers the oil holes.

The interrupter h is operated by- the roll carrier v, which
raises the interrupter lever h twice in each armature revolu-
tion. The armature and timer are both mounted on ball
bearings.

For cutting off the ignition current, a terminal screw ti;,
electrically connected internally with the primary circtiit, is
provided in the side of the large hard-rubber block of the
magneto. This terminal can be electrically connected to a
switch, preferably of the push-button type, conveniently
located. Closing the switch short-circuits the primary current
and thus stops the formation of sparks at the spark plug.

A jaw clutch X is provided for driving the armature. This
clutch has a number of teeth on its beveled inner end, so that
by loosening the nut y, the clutch can be rotatively adjusted
so as to bring the armature into the position of maximum
primary current at the proper instant relative to the time
a spark is to be produced.

The moving parts run in ball bearings that require little
lubrication, for which provision is made by holes protected
against the entrance of dust, thus insuring satisfactory
service with little attention.

Digitized by

Google

48 ELECTRIC IGNITION § 8

59. The general method of operation of the magneto in
its application to a four-cylinder engine, as shown by the
circuit diagram in Fig. 39, is as follows:

he
he

;er
ly
It;

sr-

lie
er

ty
y.

th
in
he

Digitized by

Google

§ 8 ELECTRIC IGNITION 49

secondary winding s^ of the transformer. This high-tension
current is capable of bridging the space between the ter-
minals of the spark plug. The sharper the rush of current
into the primary winding of the transformer the more easily
will the necessary intensity of pressure for a jxunp spark be
induced in the secondary winding Sj.

60. The high-tension current induced in the secondary
winding is delivered to a distributor brush carrier n that
rotates in the magneto at the same speed as the cam-shaft
of the engine. This brush carrier slides over fotu- metal
segments p^, />„ p^, and p^ set flush into the face of a large
hard-rubber block /. Each of these four segments connects
with one of the terminal sockets that are connected by cable
with the four spark plugs z. At the instant of interruption
of the primary current, the distributor brush is in contact
with one of the four metal segments and so completes the
circuit to that spark plug connected with the segment.

Should the circuit between the terminal q^ and its spark
plug be broken, or the resistance of the spark plug be too
great to permit a spark to jump, or should the discharge of
the high-tension current from the transformer be hindered
by any cause whatever, then the current might rise to an
intensity sufficient to destroy the transformer. To avoid this,
a safety spark gap z^ is introduced. This allows the pressttfe
to rise only to a certain maximum; above this maximum dis-
charges take place across the safety gap. In this type of
magneto the spark discharges across the safety gap are visible
through a small glass window conveniently located in the top
of the hard-rubber block.

MAGNETO WITH DOUBLE ARMATURE WINDING

61. What is popularly known as the U. & H. h.ifirb.-ten-
sion magpieto, shown in sectional elevation in Fig. 40, has
a rotary, double-wound armature of the shuttle type. The
primary current is interrupted to induce a secondary high-
tension current. The primary winding of the armature.

Digitized by

Google

Fig. 40 60

Digitized by VjOOQ IC

§ 8 ELECTRIC IGNITION 51

which is the inner coil, consists of a few layers of coarse
insulated wire, and the secondary winding consists of a great
number of layers of very fine insulated wire. The primary
current passes through only the timer and primary winding
of the armature. The condenser is in parallel with the timer
or interrupter. The secondary circuit comprises a slip ring
connected to the secondary winding of the armature, a col-
lector brush, a high-tension distributor, a spark plug, and
both the secondary and primary windings of the armature.
A safety spark gap is used on the high-tension circuit.

62, One end of the primary winding is grounded to the
armature itself, while the other end is connected with the
carbon brush a, which is carefully insulated from the arma-
ture shaft. Brush a bears against the interrupter block
screw 6, which in turn conducts the current to the interrupter
block c and to the condenser plate d. From the interrupter
block c the current is conducted to the interrupter lever.
This lever is in metallic contact with the body of the magneto,
and is therefore grounded, so that when the interrupter lever
is in contact with the interrupter contact screw, the primary
circuit is completed, and the primary winding of the armature
is short-circuited.

63. The beginning of the secondary winding is connected
to the end of the primary winding, being, in fact, a con-
tinuation of the primary winding. The end of the secondary
winding is connected to the armature slip ring e, which is
thoroughly insulated from the armature. From the arma-
ture slip ring the high-tension current is conducted, by means
of the brushes / to the distributor slip ring g whence it is
led to the distributor brush h by means of the distributor
stem i and the distributor brush spring seat ;. The distrib-
utor plate k is provided with as many brass distributor
segments, evenly spaced around the aistributor bore, as there
are cylinders to be fired, and as the distributor brush is
revolved, it comes into successive contact with the distributor
segments. The distributor segments are in turn connected
with the secondary terminals located at the top of the dis-

Digitized by

Google

52 ELECTRIC IGNITION § 8

tributor plate, and of which there are also as many as there
are cylinders to be fired. From the secondary terminals the
high-tension current is conducted by cables to the spark plugs
of the proper cylinders. The current, in leaping the gap of
the spark plug, is conducted to the grounded end of the plug,
from which place it returns to the groimded end of the primary
winding, through the primary winding to the beginning of the
secondary winding, thereby completing the secondary, or
high-tension, circuit.

64. At the instant of the interruption of the primary
circuit, a secondary, or high-tension, current is induced in the
secondary winding. The intensity of the current induced in
the secondary winding is nearly proportional to the intensity
of the current generated in the primary winding; hence, the
maximtun secondary effects are produced when the primary
current is interrupted at its maximum, or just as the armature
passes from one pole to the other.

Owing to its rotation in the magnetic field, the high-tension
winding generates a current in a manner similar to that
of the low-tension winding, but this current is of far greater
intensity than the primary current, owing to the difference
in the windings. The tension of this current is not sufficient,
however, to cause it to leap the gap of the spark plug, but at
the instant of interruption of the primary current, the induc-
tive effects are such as to raise the voltage or pressure of this
current to a point that will enable it to leap the gap of the
plugs. The electrical effects induced by the interruption of
the primary current are of much shorter duration than those
generated by the rotation of the secondary winding; therefore,
the generated current has its voltage increased for but an
almost infinitesimally short time. This temporary increase
enables it to bridge the air gap of the plugs, and, once bridged,
their resistance is reduced to such an extent that the current
generated by rotation, and which lasts an appreciable time,
can continue to cross. This results in a continuous flame
across the spark ^lug gaps^nd on account of its high temper-
ature and large voltune, the flame has strong ignition qtudities.

Digitized by

Google

§8

ELECTRIC IGNITION

65. The interrupter, as shown in Fig. 41, consists of the
interrupter plate a located in the interrupter housing 6.
Attached to the interrupter plate is a stud c on which is
pivoted the interrupter lever d. The interrupter lever is
provided with a platinum-pointed contact screw e, and is nor-
mally held by the flat spring / in contact with the platinum-
pointed interrupter contact screw g. The interrupter contact
screw is connected to the end of the primary winding.

Keyed to the interrupter end of the armature shaft, and
rotating positively with the armature, is the interrupter-cam
housing /, Fig. 40. Securely attached to the interrupter-cam

Fig. 41

housing is the interrupter cam, consisting of a ring of hard
fiber, having on its inner face two projections, or cam faces.
The interrupter housing b, Fig. 41, is held in accurate
alinement with the interrupter cam by the construction of
the rear end plate, and as the armature revolves the pro-
jections of the interrupter cam are brought into contact with
the interrupter cam pin A, causing a movement of the inter-
rupter lever d sufficient to separate the contact screws e and g
ancl thereby interrupt the primary circuit, twice in every
revolution. As the projections continue to revolve, the
interrupter lever d instantly resumes its normal position, and
completes the primary circuit.

Digitized by

Google

54 ELECTRIC IGNITION § 8

66. The safety spark gap w, Fig. 40, is formed by bring-
ing the distributor-cover screw n to within a certain distance,
which is generally about f inch, from the end of the distributor
stem o. The distributor cover screw is grounded to the mag-
neto, thereby providing a path for the high-tension current
should the voltage become high enough to cause it to leap the
safety spark gap. The user is cautioned against allowing
the discharges to pass across the safety spark gap for any
length of time, as it places the high-tension insulation under
a continuous and abnormal stress.

67. A starting device is provided with this magneto.
It is arranged for furnishing a current arid spark strong
enough to produce ignition in the cylinders even when the
shaft that is driving the magneto is rotating at very low speed ;
that is, even though the rotary movement of the driving shaft
is so slow as to be practically imperceptible. This is accom-
plished by the use of an automatic lock for the armature and
a coiled spring p. Fig. 40, between and attached to the arma-
ture driver q and the driving flange r for driving the armature.
When the armature driver is rotated slowly, the armature is
locked, so as to prevent its rotation during part of a revolution
of the shaft. The coiled spring is still further coiled against
its resistance during the time the armature is locked and its
driving shaft is rotating slowly. The armature is then auto-
matically released and snapped forwards suddenly by the
uncoiling of the spring. The movement of the armature
secured in this manner is rapid enough to produce a spark
in the cylinder under compression. The construction is such
that the release and spark occur at the proper time for ignition
when starting the engine by hand cranking. As soon as the
speed is increased by an impulse in the engine cylinder, the
device that temporarily locks the armature is thrown out of
action and the armature rotates with its driving shaft.

Digitized by

Google

§8

ELECTRIC IGNITION

ps.k*

"^Z-

r4*

—JJ

li"^

h\^

-fr—

MAGNETO WITH STATIONARY ARMATURE

68. The BoBcli lilgli-tenslon magneto has a sta-
tionary double-wound armature and a rotary magnetic screen
of the form shown in Fig. 42. It is operated on the inter-
rupted primary-current system. The armature a is stationary
in the position shown, and it is enough smaller than the pole
pieces b to permit a soft-iron segmental screen c to pass
between them. The segmental screen pieces are mechanically
mounted on non-magnetic heads, to which the spindle or the
shaft is attached. The effect of this screen is to divert the
lines of force at each eighth of a revolution, sending them
alternately through
the stem of the
armature core and
through the ends,
as shown by the
dotted arrows. This
reverses the cturent
four times in each
revolution instead of
twice, as is the case
with the ordinary
rotating shuttle-
wound armature.

69. Referring to ^^- ^

Fig. 43, which is a sectional elevation of the magneto,
and to Fig. 44, which is a conventional wiring or circuit
diagram, it will be seen that one end of the primary
winding is electrically connected to the armature core a and
that the other end is connected to the brass tube 6, which
is mounted in the rear portion of the armature spindle and is
insulated through it. The conducting bar c is firmly secured
to this tube, the end of which extends beyond the spindle of
the armature, and the primary current is conducted by means
of the bar c to the contact piece d, which is provided with a
platinum contact screw e. A contact piece in the upper end

Digitized by

Google

56 ELECTRIC IGNITION § 8

of the interrupter lever / is normally held against the screw e
by action of the compressed spring g. A recessed disk h
rotates with the magnetic shield t. The lobes on the disk h
strike the lower end of the interrupter lever / and move it so
as to break the contact between the lever and screw e. The
interrupter lever is in electrical contact with the frame of the
machine, and consequently with one end of the groimded
primary winding. When the interrupter lever / is in contact
with the screw e, the circuit is closed through the brass tube 6,

Pig. 43

the conducting bar c, the contact screw e, the lever /, the
frame of the machine, and the core of the armature. One
of the terminals of the condenser ; is connected to the con-
tact piece d, and the other terminal is connected to the body
of the machine. The condenser is thus connected in parallel
with the contact breaker.

70. The secondary winding is a continuation of the
primary winding, their adjacent ends being soldered together.
The other end of the secondary winding is connected to the

Digitized by VjOOQIC

§8

ELECTRIC IGNITION

small insulated tube k. The bent carbon holder / passes
through the rear portion of the armature spindle; one end
of the carbon holder is fitted into the insulated brass tube k
by means of a small plug. The secondary ctmrent passes
from the armature through the small plug and bent carbon
holder to the carbon brush w, which conducts the current to
the slip ring n of the high-tension distributor disk o. The
distributor segment p may be considered as a distributor
arm that comes successively into contact with the four
high-tension carbon distributor terminals q. Each of the

Fig. 44

temjinals q is connected to its own insulated tubular con-
ductor in the terminal block. Above the terminal plate is
a removable plug contact piece that carries four insulated
plugs, each of which slips into contact with its tubular mate
in the terminal block. The upper ends of the plug contact
pieces are threaded so as to provide for making screw con-
nections to the wires leading to the spark plugs.

71. The path of the high-tension current is through the
secondary winding of the armature, the brass tube k, the
bent carbon holder /, the distributor disk o, the current-
collecting carbons in the carbon holder q, the conductors in

222B— 28

Digitized by

Google

68 ELECTRIC IGNITION § 8

the terminal block, the plug contacts, the wire leading to the
ignition plug, the engine, and the frame of the machine to
the armature core, and then through the primary winding
to its junction with the secondary winding.

A safety spark gap s is provided between the low-tension
conducting bar c and the high-tension carbon holder /. This
allows a spark to jump between the extended ends of the
primary winding when an excessive pressure occurs.

The speed of the rotor of the magneto, when supplying cur-
rent to the iouT spark plugs of a four-cylinder four-cycle
engine, is the same as that of the half-speed shaft, or cam-
shaft, of the engine. This speed is only half as fast as the
speed of the crank-shaft. For a two-cylinder four-cycle
engine, the magneto rotor can be run at the same speed as for
a four-cylinder engine of the same type, two of the high-
tension terminals being short-circuited to the frame or body
of the magneto. In a two-cycle four-cylinder engine, the
magneto speed is the same as that of the crank-shaft.

72. The mechanical connection for rocking the timer by
hand is made at the arm r. Fig. 43. The four- terminal timer
shown is constructed to rock S(f, corresponding to 60^ rotation
of the crank-shaft in a four-cylinder four-cycle engine. The
same angle values apply to a two-cylinder four-cycle engine
using only two of the high-tension terminals. On a four-
cylinder two-cycle engine, the angles of the timer rock and
crank-shaft rotation are equal. When the magneto is pro-
vided with six high-tension terminals for a six-cylinder engine,
instead of four terminals as illustrated, the magneto rotor
speed is one and one-half times that of the cam-shaft for a
four-cycle engine; the magneto rotor makes three revolutions
during four revolutions of the engine crank-shaft. In the six-
cylinder four-cycle engine, a 30^ rock of the timer corresponds
to 40° rotation of the crank-shaft.

Digitized by

Google

Digitized by

Google

60 ELECTRIC IGNITION § 8

MAGNETO WITH STATIONARY WINDING

73. The Pittsfield liig^li-tenBion mag^netp, which
has a stationary winding, is illustrated in Fig. 45 (a) and (6).
The north and south pole pieces of the permanent magnet are
at N and S. A magnet core made up of soft-iron stampings
and placed at right angles to the permanent magnet has its
laminated pole pieces E and F located as illustrated. A
non-vibrating induction coil c is located on what corresponds
to the crown of the magnet core. A rotor somewhat in the
form of the magnetic screens referred to in Art. 68, but
thicker radially, lies in the bore between the magnet poles.

The laminated soft-iron rotor a b revolves in the magnetic
field produced by the permanent magnets. The rotation of
the armature a 6 in the magnetic field generates in the wind-
ing of coil c an alternating current that attains a maximum
value four times during a complete revolution of the armature.

74. The primary winding, which is next to the core d,
consists of a few turns of heavy wire ; one end of this wire is
connected to the body of the machine, and the other end is
connected to a contact plate insulated with hard rubber.
From this plate a wire makes a connection to the contact
piece and platinum screw of the interrupter, the contact piece
being insulated from the interrupter, which is in metallic con-
nection with the field or ground. The current generated in
the primary winding is therefore short-circuited as long as the
contact piece and platinum screw of the interrupter are in con-
tact with each other. The primary current is interrupted
at the instant that the interrupter cam e moves the interrupter
lever. A condenser /, protected by an aluminum housing g,
is connected in parallel with the contact points of the
interrupter.

75. The beginning of the secondary winding, which con-
sists of many turns of fine wire, is connected to the end of the
primary; the other end leads to contact button h of the coil.
The secondary current is conducted from button h to the brass
distributing segment i by means of the carbon brush and its

Digitized by

Google

§ 8 ELECTRIC IGNITION 61

spring y, to the conductor k^ which is insulated by hard-rubber
piece /, and to the distributor segment i. The segment i is
insulated by the hard-rubber piece m. In the front end plate n
are inserted four high-tension terminals. During a revolution
of the rotor the segment i comes into successive contact with
all the high-tension terminals. From the high-tension ter-
minals the current is conducted to the socket inserts in the
distributor plate o by means of connections p. From the
socket inserts the high-tension current is conducted, by means
of cables, to the spark plugs of the cylinders in the order
required. The interrupter is screwed on one of the heads of
the magnetic screen, and can be easily removed. The primary
circuit is four times interrupted and short-circuited during
each turn of the armature. This is accomplished by means of
the four-lobed cam e rocking the interrupter lever. This cam
revolves with the rotor of the magneto.

76. The four sections q of the magnetic screen are
mounted on non-magnetic heads concentric with the rotor.
The interrupter lever, together with the contiguous parts of
the interrupter, is mounted on one of these heads. The time
of ignition is varied by rocking the interrupter and the mag-
netic screen on which the interrupter is fastened. For this
purpose the screen sleeve q is fitted with a lever to which con-
nections leading to the spark control can be attached. The
time adjustment is S(f at the timer, which corresponds to 60^
at the engine crank-shaft of a four-cylinder four-cycle engine.

77. The action of the magneto depends on the alternate
magnetizing and demagnetizing of the magnet core on which
the coil c is mounted, thus inducing an electric current in the
coil. This is accomplished by bridging the air gaps between
the permanent magnet poles and the poles of the soft-iron
laminated magnet core on which the transformer coil is
mounted. The manner in which this occurs during the
rotation of the rotor, can be seen by referring to Fig. 46.

In Fig. 46 (a) the position of the rotor is such that the few
magnetic lines that pass through it go from N to S without
passing into the soft-iron magnet. When the rotor has turned

Digitized by

Google

ELECTRIC IGNITION

to the position shown in (6), the magnetism flows from the
permanent pole N through the side b of the rotor to the pole F
of the soft magnet core. From F the magnetism flows
through the core of the transformer coil c, Fig. 45 (6), and on
to the pole E. From E the path of the magnetic flux is
through the side a of the rotor to the pole S of the permanent
magnet. When the rotor reaches the position shown in (c) there
is practically no magnetic flux through the induced magnet.

Fio. 48

A.ny flux that occurs follows the path indicated by the arrows.
In the position of the rotor shown in (d), the magnetic flux,
as indicated by the arrows, is through the soft magnet core
and the transformer in a direction opposite that shown when
the rotor is in the position (6). A complete cycle, compri-
sing two reversals of the current and the corresponding two
maxima of positive and negative pressures, takes place dur-
ing a half revolution of the engine. The current therefore
has maximum values four times per revolution of the engine.

Digitized by

Google

ELECTRIC IGNITION

(PART 4)

SPARK CONTROL

CJONTROL OF SPARK ADVANCE

INTRODUCTION

!• Methods of Producing Spark. — In modem auto-
mobile igniticm, the jump-spark, or high-tension, ignition system
is used exclusively. The current may be obtained from a high-
tension magneto, which generates current having a high volt-
age; from a low-tension magneto or dynamo, which generates
current having a low voltage; or, from a storage battery or
a dry-cell battery. When current is obtained from any source
except a high-tension magneto, an induction coil must be used
to increase the voltage sufficiently to cause an electric spark
to jump the air gap in the spark plug. The high-tension
magneto does not require the use of a separate induction coil,
for it contains within itself primary and secondary windings
that serve the purpose of a coil and enable the magneto to
produce a current having a high voltage. With a battery and
a separate induction coil, the primary circuit must be closed
by the timer and opened by the vibrator of the coil, or both
closed and opened by the timer in the case of a non-vibrator
coil, in order to obtain a current in the secondary winding;
with the high-tension magneto, the primary circuit must be
interrupted by a circuit-breaker, or interrupter, in order to
induce a current of high voltage in the secondary winding.

COmiiaHTBD BY INTKRNATIONAL TSX TBOOK COMPANY. ALL MOHTS RBSKIIVBD

Digitized by

Google

64 ELECTRIC IGNITION • §8

2. Spark-Tlme Variation. — The power generated in the
cylinder of an automobile engine depends to a large extent
on the time at which the primary circuit is interrupted, because
it is then that the spark is formed and the combustible mixtiu^
ignited. In order to obtain the very best results from each
explosion, the spark should occur at the most advantageous
point in the compression stroke of the engine. This point
varies with diiferent engines and depends on the size of the
combustion chamber, the degree of compression in the cylin-
der, and the speed of rotation of the engine.

The time at which the spark should occiu* depends on the
size of the combustion chamber, because, with a small cylin-
der, less time is required to ignite the mixture completely;
hence, the spark need not occur any appreciable length of time
before the crank reaches its upper, or outer, dead center.
With a larger cylinder and combustion chamber, a longer time
is required for complete ignition; therefore, the spark must
occur earlier. The time of ignition depends on the degree of
compression in the cylinder, because, if the combustible mixture
is very dense, it will biun more rapidly than if it is not com-
pressed to so high a degree; therefore, with high compression in
a cylinder, the spark need not occur so early as with low ,
compression. The speed of the engine influences the time of
ignition, because with a high piston speed there is less time
for the mixture to bum than with a low piston speed; hence
the spark should be advanced farther, and ignition must occur
earlier, for a high engine speed than for a low engine speed.

3. Methods of Spark-Tlme Control. — ^With an internal
combustion engine that runs at a constant speed, the spark
should always occur at the same point in the compression stroke,
because the three factors that affect the timing of the spark
remain constant all the time the engine is running. Hence,
with such an engine, there is no necessity of providing means
for varying the timing of the spark and none is provided; or,
in other words, Si fixed sparky as it is called, is used. With an
automobile internal-combustion engine, however, the speed of
the engine varies necessarily between wide limits; hence, if a

Digitized by

Google

§8 ELECTRIC IGNITION 65

fixed spark is used, it will produce the best results at the one
engine speed for which it is fixed, and inferior results at other
engine speeds. In spite of this fact, a fixed spark is used in
some automobiles for the sake of simplifying the control of the
machine.

If it is desired to obtain the best possible burning of the fresh
charge at all engine speeds, means must be provided for vary-
ing the time at which the primary circuit is either closed or
broken while the engine and the automobile are in motion. An
ignition system in which the timing of the spark can be varied
by hand is said to have a variable^ or hand spark, control; if the
timing is varied automatically by a change in the engine speed,
the system is spoken of as having an automatic spark control,
or a governor control.

HAND SPARK CONTROL

4. Operation. — The most nattiral, and, consequently, the
most common, method of controlling the spark advance is by
hand-operated means. On the majority of automobiles, the
timer or the interrupter is operated through rods and levers
from the hand lever on the steering post. Usually, a rod
extends downwards through the center of the steering colimm,
although, in some cases, this rod is placed alongside the colimm,
and is connected by other rods and levers to the movable part
of the timer or of the interrupter. The upper end of the rod
in or alongside the steering column is turned by a hand lever.
If the lever is moved in one direction, it rotates the timer or
interrupter and causes the spark to occur earlier, but if it is
moved in the opposite direction, it causes the spark to occur
later.

5. In many cases, it is impossible to tell at the first glance
which is the spark lever and which is the throttle lever, neither
one being marked to indicate its purpose. In other cases,
either the two levers or the quadrants over which the levers
slide are plainly marked to indicate their purpose, the spark
lever usually being indicated by the letter S and the throttle
lever by the letter T. However, as the spark lever is connected

Digitized by

Google

66 ELECTRIC IGNITION §8

to the timer or interrupter and the throttle lever to the
carbureter, these levers can be located on a car with which
a person is not familiar by simply removing the engine hood
and observing whether the rod running to the timer or the
interrupter or that leading to the carbureter is moved when
one of the levers is pushed forwards or backwards.

Another point to remember is that the direction in which
the hand lever must be moved to advance or retard the spark
is not the same on all automobiles. Sometimes it must be
ascertained by experiment or from the rtianufactiu-er's book of
instructions.

6. In an engine that is fitted with two independent ignition
systems, as a battery system with an induction coil and a timer,
and a magneto system, the circuit-breaking mechanism of the
magneto is usually interconnected with the timer of the bat-
tery system, or the circuit-breaking mechanism of the magneto
and the timer of the battery system are connected separately
to the same spark lever, in such a manner that the circuit-
breaker and the timer will move simultaneously. The mag-
neto circuit-breaker and the battery-system timer are usually
so adjusted with reference to each other that the spark will
occur in the engine cylinder at the same point of the piston
stroke, irrespective of whether the battery ignition system
or the magneto ignition system is used. This means that the
position of the spark lever for any given point of ignition is
the same for both ignition systems.

7« Example of Hand Spark-Control Construction.

The spark-control mechanism for a double ignition system
is illustrated in Fig. 1. This illustration shows the connec-
tions on the Peerless six-cylinder engine, which makes use of
two entirely independent systems of ignition, one employing
a battery and separate timer and the other a magneto and
magneto interrupter.

The spark lever a is connected by means of the spark advance
rods b and c to the small bell-crank d. The spark advance
rod b is connected to the rod c at the bottom of the steering
coltimn by means of a screw-and-nut connection / and levers k

Digitized by

Google

Digitized by

Google

68 ELECTRIC IGNITION § 8

and /, which are pivoted at m. The two levers k and / are
fastened to the same shaft and hence move together. The
lower end of the rod b contains a screw thread that turns in a
nut carried by the lever k\ thus, when the spark lever is moved,
the screw is rotated and the nut moved up or down, and the
rod c is thus shifted by means of the levers that are joined
at m. The small bell-crank is connected at ^ to the movable
part of the timer, which is located in the vertical column /;
therefore, any movement of the hand lever a causes a corre-
sponding movement of the timer. The rod g connects the
bell-crank d with the magneto interrupter at /t, so that a move-
ment of the hand lever also rotates this circuit-breaker. By
means of these connections, both the timer and the magneto
interrupter are controlled by the same hand lever, and hence
the spark advance is controlled in the same manner whether
the battery ignition system or the magneto ignition system is
used.

8. The Peerless system of hand spark control is only one of
a large ntmiber of different methods of connecting the hand
spark lever and the timer and interrupter. In some cases,
the timer or interrupter is so located that the spark advance
rod in the steering column is connected directly to it by a single
rod. In other instances, the spark advance rod is not located
inside of the steering colimin, but is placed along the outside
of it, and the spark lever is imder the steering wheel. In some
cases the spark lever is placed on the dash. In any case, it is
well for the driver to know how the connections are made on
his car, and he should familiarize himself with them so as to
be able more readily to locate and remedy trouble.

GOVERNOR 6PARK CONTROL

9. Principle of Operation. — In order to do away with
the necessity for a spark-advance hand lever on the steering
wheel, and thus simplify the control of the engine, and yet
obtain the spark at the proper time, an automatic governor
control is used in some magneto ignition systems. When this

Digitized by

Google

§8 ELECTRIC IGNITION 69

control is used, the steering-wheel hand spark lever and all the
connections to the- magneto are eliminated, so that the driver
need manipulate only the throttle lever; the spark advance
is taken care of by the governor.

10. Automatic control of the spark advance is based on
the fact that a weight revolved around an axis not passing
through its center of gravity, moves away from this axis unless
restrained, the force causing this outward motion being known
as centrifugal force. In practice, two or more equal weights
are employed; these are so distributed as to be in balance,
in order that harmful vibrations may not be set up when the
weights are revolving at high speed. The weights of the gov-
ernor are either incorporated in the magneto itself or they are
placed in a coupling between the magneto drive shaft and the
magneto armature; they are arranged so that when the speed
of the magneto is increased they fly outwards and by the assist-
ance of proper mechanism change the position of the armature
relative to the pole pieces, thus causing the spark to occur
earlier. As the engine, and, consequently, the magneto gov-
ernor, slows down, the weights move in again and thus retard
the spark. By the use of the governor control, the spark is
advanced when the engine speeds up and retarded wheri it
slows down, without any attention from the driver.

11. Some practical examples of automatic governor control
are the Eisemann automatic advance, the Franklin governor
control, the multiple-ball coupling control, which is used on
the Simms magneto and the Herz-Ruthardt magneto, and
the Atwater-Kent automatic advance.

12. Eisemann Automatic Spark Control.— In the

Eisemann automatic spark control, the spark advance is accom-
plished by means of an automatic governor attached to a reg-
ular high-tension magneto. The complete magneto is illus-
trated in Fig. 2, which shows the end casing a removed so as
to expose the governing mechanism. The magneto is fitted
with a shuttle-wound armature, which contains both primary
and secondary windings and is driven through the governor
from the shaft b. The interrupter, located at c, is so arranged

Digitized by

Google

70 ELECTRIC IGNITION § 8

that if the position of the annature relative to that of the shaft b
is advanced, the primary circuit will be broken earlier in the
engine cycle and the spark advanced. In a similar manner,
if the position of the annature is retarded, the spark also will
be retarded. The governor is so constructed that the arma-
ture is advanced when the engine is speeded up and retarded
when the engine is slowed down; thus, the spark is controlled
automatically.

13. The Eisemann automatic advance mechanism in place
on the armature shaft, just as it is used in the magneto, is
illustrated in Fig. 3, which also shows the different parts in
detail. The armatiu-e a, which revolves between the magnets

Pig. 2

of the magneto, is carried on the three bearing^ 6, c, and d,
and is driven through the governing device from the shaft e.
The gear / drives the high-tension distributor. The shaft e
is driven by gearing from the crank-shaft, and it, in turn, drives
the guide g, which is rigidly attached to the armature. The
nut, or sleeve, h slides in the guide g and is turned by the shaft e
through ridges or long threads that run the length of the shaft
and partly arotmd it and fit in corresponding grooves in the
sleeve. The sleeve h is held in the outer end of the guide by
a spring /, which siurounds the shaft and presses against the
inner end of the gtiide g. Two weights k are connected to the
outer end of the sleeve by arms /, and are hinged to the guide g

Digitized by

Google

§ 8 ELECTRIC IGNITION 71

by pins m. The shaft e is not connected to the guide g except
through the sleeve h and the weights k.

When the- engine speeds up, centrifugal force pulls the
weights k away from the shaft, thus causing the sleeve fc to be
drawn in against the pressure of the spring ; and to be slid on
the shaft e. As the sleeve h is thus moved toward the arma-
ture, it is turned, relatively to the shaft e, by means of its
grooves, which fit over the long ridges, or threads, on the shaft e.
This relative rotation of the sleeve turns the guide g, and con-
sequently the armatiu*e, forwards on the shaft e. The primary
current is thereby interrupted earlier in the rotation of both the
shaft e and the engine crank-shaft, and, as a result, produces

SV"-^^

Fig. 3

earlier ignition of the charge in the cylinder that is to be fired.
As the engine slows down, the weights move in toward the shaft,
and, with the help of the spring, they push the sleeve out,
thereby allowing the armature to shift its position backwards
in relation to that of the shaft. This causes the primary
current to be interrupted and the spark to be formed later in
the cycle of the engine.

14. Franklin Governor Si>ark Control. — ^The auto-
matic spark control employed on the Franklin automobile
makes use of the same principle as is employed in the Eise-
mann magneto; that is, the magneto armature is driven through
an automatic governor that regulates the spark advance.
Fig. 4, which is a diagrammatic illustration, shows the location

Digitized by

Google

ELECTRIC IGNITION

§8

of the magneto a an(J the governor 6 on a six-cylinder engine,
the governor being driven through the shaft c by means of the
helical gear d, which meshes with the gear e on the cam-shaft.
The magneto armature is connected by a short shaft to the
governor casing, from which it receives its motion. The con-
struction of the governor is such that, when the speed of the
engine exceeds about 300 revolutions per minute, the casing
is advanced slightly ahead of the shaft c and the armature
of the magneto is thus moved ahead relative to the position of
the crank-shaft. This causes ignition to occur earlier in the

Fig. 4

cycle of the engine, and it has the same eflfect as advancing
the spark by hand. As the speed of the engine decreases, the
opposite action takes place and the spark is retarded.

15. The governor proper consists essentially of a circular
casing keyed to the armature shaft and two weights mounted
inside the casing. As illustrated in Fig. 5 (a), the casing is
made up of two sections d and e that are held together at the
joint/ by the capscrews g; the section d is keyed to the armature
shaft d\ Views (b) and {c) show the arrangement of the dif-
ferent parts in the sections d and e when separated and viewed
from the open ends thus made. The section d, view (fc), con-
tains weights h that are pivoted to the casing at / and are pro-
vided with gear-teeth k that mesh with the teeth on the pinion /.
The pinion is fitted to the end of the drive shaft m, which
is connected to the casing only through the pinion and
weights. The springs n hold the weights in position against

Digitized by

Google

§8

ELECTRIC IGNITION

the stop-studs o when the engine is not running, or when it is
running very slowly.

In the smaller section e of the governor is contained a small
friction brake that assists in preventing the governor from act-
ing at low speeds. This brake is shown in view (c), and consists
principally 'of two springs ard plimgers and a friction strap.
The spring seat p is pinned to the drive shaft m and turns

«3cK

(b)

<c)

Fic. 5

with it, carrying around the springs q and plungers r. Each
spring holds the end of a plunger in the notch s of the strap t,
which is riveted to the casing, and tends to prevent the casing
from turning relative to the sliaft, so that the governor will not
act at low speeds. At high speeds, the action of the governor
is suflficient to force the plungers out of the notches and move
the casing ahead of the drive shaft.

222B-20

Digitized by

Google

74 ELECTRIC IGNITION §8

When the speed of the engine reaches a certain point, the
resistance of both the friction brake and the springs n is over-
come and the weights h fly out sufficiently to cause their teeth
to turn on the pinion. This action forces the weights and the
casing ahead of the pinion and the drive shaft; and, as the casing
is keyed to the armature shaft, it also is advanced relative to
the drive shaft. As the drive shaft is connected by gears to the
engine crank-shaft, the governor advances the magneto arma-
ture in relation to this shaft; hence, by this arrangement, the
spark is made to occur earlier in the cyde of the engine. When
the engine slows down, the weights resume their original posi-
tions and the spark is again retarded.

16. MuItlpIe-Ball Coupling Spark Control. — ^The
fundamental principle of operation of the multiple-ball coup-
ling spark control is the same as that of the Eisemann and
Franklin automatic spark controls; that is, the armatiu*e shaft
of the magneto is driven through a coupling that acts to advance
the relative position of the armature as the speed increases
and to retard it as the speed decreases. The coupling is located
between the magneto drive shaft and the armature, and con-
sists of two halves in the form of disks, which are connected
by means of steel balls placed in curved grooves formed in the
disks. The grooves in the two disks are of opposite curva-
tiu^, so that when the action of centrifugal force throws the
balls outwards and away from the center, the driven disk is
advanced in relation to the other, in order to make room for
the balls farther out in the grooves. This action occurs when
the magneto speeds up, so that it has the effect of advancing
the position of the armature, and, consequently, the time of
ignition, at high engine speeds.

17. The construction of the multiple-ball coupling, or
governor, used on the Herz-Ruthardt magneto is illtistrated
in Fig. 6. This coupling contains six steel balls a that connect
the disks b and c through the grooves d and e. The disk b is
fixed on the armatiu^ shaft and is driven by the disk c, which
is secured to the magneto drive shaft. The grooves d and e
are curved in opposite directions, so that when the coupling

Digitized by

Google

§ 8 ELECTRIC IGNITION 76

is assembled, as shown, and the drive shaft speeds up and the
balls move out from the center, they force the disk b ahead
of the disk c and thus advance the armatiu'e. As the speed
of the engine and that of the magneto drive shaft decreases,
the balls assume their original position near the center of the
coupling and the annatiu'e is retarded accordingly. The
armature shaft and magneto drive shaft are kept in alinement
by means of an exten-
sion g on the disk b,
which fits in the hole h
in the disk c,

18« The auto-
matic governor, or
coupling, used on the
Simms magneto is
slightly different from
the Herz-Ruthardt
coupling, in that the
disks are not fi^t and
fewer balls are em-
ployed. In this de-
vice, one disk is convex
and the other is hol-
low ; thus, the coupling

remains in alinement Pic. e

without any special

extension or swivel. The multiple-ball coupling may be used
on any suitable magneto by simply inserting it between the
drive shaft and armatiu-e shaft and without altering the design
of the machine; the magneto must have its interrupter mecha-
nism so arranged that the part not attached to the armatiu-e
remains stationary in respect to the pole pieces.

19« Atwater-Kent Automatic Spark Control. — ^The
Atwater-Kent automatic spark-control mechanism, which is
designed to be used in connection with the Atwater-Kent sys-
tem, type K, operates on exactly the same principle as the

Digitized by

Google

76 ELECTRIC IGNITION § 8

automatic governors previously described. It is a modifica-
tion of the ordinary centrifugal governor. The governing
device is contained in the same casing as the primary circuit
breaker and the high-tension distributor, and acts as a coupling
through which the circuit breaker is driven. One side of the
governor is connected to a vertical shaft that is driven by the
cam-shaft, and the other side to a short shaft that is enclosed
in the casing and operates the apparatus making and breaking
the primary circuit. The instant at which the primary circuit
is broken is automatically varied by centrifugal force acting
upon the governor weights.

20. The principle of operation of the Atwater-Kent gov-
erning device is shown diagrammatically in Fig. 7. The
governor is composed essentially of foiu* weights. These are

connected to the
short shaft that oper-
ates the circuit
breaker and the ver-
tical driving shaft by
two arms, one at the
top of the device and
one at the bottom.
In order to simplify
pjq y the illustration, only

two weights are
shown. These weights are marked a and a'. The upper
weight a is connected to the arm b by the pin c, and the lower
weight a' to the arm b' by the pin c\ The weights are pivoted
together at their center by a pin d. The lower arm 6' is rigidly
attached to the vertical driving shaft e, and the upper arm b is
rigidly attached to the shaft /, which is part of the circuit-
breaker. In order to prevent the weights from moving out
too rapidly, they are cormected to the arms by springs g and g',
against which the centrifugal force must act.

When the vertical shaft e rotates, it drives the short shaft /
through the governor weights and arms. If, at any time
the speed of the shaft e is increased, there is a corresponding

Digitized by

Google

§ 8 ELECTRIC IGNITION 77

increase in the centrifugal force acting on the weights, and they
will move outwards from their original position a distance
depending on the amotmt of increase in speed. As the weights
move outwards, or away from the shaft, they rotate in relation
to each other about the pin d, so that the pin d also moves away
from the center of the shaft. Since the weights are connected
to the arms at opposite ends, they tend to turn the arms in
opposite directions as they fly outwards; that is, to draw the
points c and c' toward each other. The result of this move-
ment is to change the relative positions of the shafts e and /,
and thus, as the speed of the governor is increased, to move
the shaft / ahead of the shaft e in the direction of rotation.
In the actual device, the shaft / operates the circuit-breaking
mechanism; hence, the primary circuit is broken earUer in the
stroke of the engine piston when running at high speed than
when running at low speed. If at any time the engine, and,
consequently, the governor, slows down, the weights move in
toward the vertical shaft; in such an event, the shaft/ is rotated
in relation to the shaft ^ in a direction opposite to that in which
the mechanism is turning, with the effect that the primary
circuit is broken later in the stroke of the engine and the spark
is retarded.

21. The actual arrangement of the parts of the Atwater-
Kent governor is illustrated in Fig. 8, which shows the gov-
ernor mechanism mounted in the casing. The fotu* weights arc
shown at a and a', each pair being pivoted together at d and d' ;
the two arms are shown at b and 6' ; and the springs, at g and g'.
The slotted shaft / operates the circuit-breaking mechanism by
means of four indentations, one of which is shown at h. These
indentations form a ratchet that engages with the circuit-
breaker trigger arm and thus actuates the circuit-breaking
mechanism. The driving coupling ; connects the device with
the vertical driving shaft. The arm b is rigidly attached to
the shaft /, and the arm 6' is rigidly secured to the driving
coupling.

The principle of operation explained in connection with the
diagram in Fig. 7 applies directly to the real device. On

Digitized by

Google

78 ELECTRIC IGNITION §8

referring again to Fig. 8, it will be evident that when the speed
of the engine, and, hence, that of the governor, is increased,

the weights a and a'
I will fly outwards or
away from the center
of the governor and
will draw the arms b
and b' with them,
thereby moving the
shaft / ahead of the
driving shaft in the di-
rection of rotation
and thus advancing
the time of ignition.
When the speed of the
engine decreases, the
weights will move in-
wards, or toward the
center of the gov-
ernor, and the shaft/
will lag behind the
driving shaft, so that
the spark is retarded.

FIXED 6PABK

22. The point at
which the spark oc-
curs in the cylinder
of an automobile en-
gine may usually be
varied, either auto-
matically or by hand,
while the engine is
^°-® running, because it

is desirable to advance the spark as the speefd of the engine is
increased and to retard it as the speed is decreased in order to
allow the combustible mixtiu-e the proper length of time to

Digitized by

Google

§ 8 , ELECTRIC IGNITION 79

bum. However, in the case of smaller engines, the time
required for the propagation of the flame is very short, and the
variation of the spark does not have so great an influence on
the power developed as it does in the case of larger engines.
On account of this fact, and in order to simplify the control of
the engine, some of the smaller pleasure automobiles and a
number of commercial vehicles make use of what is known as
the fixed spark.

23. In the fixed-spark system, the time at which ignition
takes place is fixed in one position and no spark control lever
or automatic governor is used. Hence, the spark always occurs
at the same point in the piston stroke and is generally set with
a slight advance, that is, to occur immediately before the piston
reaches its dead-center position, so as to allow time for the flame
to propagate.

24. The advantage of the fixed spark is its simplicity,
because, when it is used, the control of the engine is reduced
to the manipulation of the throttle lever only. The fixed spark
is used extensively on motor trucks in order to protect the
engine as far as possible from injury through the imskilful use
of the spark control. .

SPARK LNTENSITY

FACrOBS AFFBCTINO SPABK INTENSriT

25* When a battery ignition system is used, the primary
current has the same strength, regardless of the timing of the
spark, in relation to the stroke of the «igine piston, and hence
a spark of the same intensity is obtained throughout the whole
spark range, from fully retarded to fully advanced. The
intensity of the spark is not aflfected in any way by the speed
of the engine, because the source of the current is independent
of the engine. It is assumed in this discussion that the battery
gives a current of sufficient strength to produce a spark.

26. When either direct-current dynamos or magnetos are
used for ignition, they are driven by the engine; hence, in a

Digitized by

Google

80 ELECTRIC IGNITION §8

general way, the strength of the primary current as well as
the intensity of the spark varies with the speed of the engine,
being least at low engine speeds and highest at high engine
speeds. There is an exception, however, in the case of non-
synchronous friction-driven dynamos and magnetos with a cen-
trifugal governor control. In these, the governor prevents the
armature from exceeding a certain maximimi speed, and,
consequently, there is a limit to the spark intensity, which
limit is usually somewhat below that obtainable at the highest
engine speed, provided the armatiu*e is positively driven.

27. Every direct-current dynamo used for ignition, and at
least one form of synchronous alternating-current magneto,
which is constructed with a large number of pole pieces, merely
takes the place of the battery as a source of current, and is
tised in conjunction with a timer, or with a distributor and
timer, depending on whether there is an induction coil for each
cylinder, or a single induction coil for all the cylinders. In such
dynamos and in such a magneto, the intensity of the primary
current is practically constant throughout the whole revolu-
tion of the dynamo or magneto armature, and, as a result, a
spark of practically tmiform intensity is obtained through the
whole spark range, the spark intensity vaxymg only with the
armature speed.

28. Synchronous-ignition magnetos usually generate an
alternating current; they have a primary circuit-breaker — ^that
is, an interrupter — and a high-tension distributor incorporated
in their construction. With all such magnetos, regardless of
whether they generate the high-tension current directly in the
magneto or in a separate induction coil, the spark intensity
varies with the armature speed; the spark intensity through
the spark range may be uniform or practically tmiform, or it
may vary between wide limits at a given armattire speed,
depending on the construction of the magneto.

29. Many synchronotis magnetos are built for dual ignition,
the second ignition system employing current from a battery,
using either the same or a separate circuit-breaker operated by
the rotation of the armature for breaking the battery current.

Digitized by

Google

§ 8 ELECTRIC IGNITION 81

an induction coil for the secondary current of the battery system,
and the regular magneto distributor for distributing the high-
tension current when the battery system is in use. With such
magnetos, the spark intensity, when the battery system is
in use, is uniform throughout the whole spark range and is
independent of the magneto armature speed. When the mag-
neto system is in use, the spark intensity varies with the arma-
ture speed and may or may not vary through the spark range.

INTIfUENCE OF SPARK INTENSITY ON STARTING ENGINE

30. From the statements made in Arts. 25 to 29, inclusive,
it should be apparent that, with a battery system, the engine can
be cranked with the spark fuUy retarded so as to prevent a back-
fire; also, that the cranking can be done at a very low speed,
because the spark intensity is independent of the engine speed.

When the ignition is furnished by a dynamo or a magneto
giving the same, or practically the same, spark intensity through
the whole spark range, the engine can be cranked with the spark
fully retarded. Since the strength of the secondary current
varies with the armature speed, the engine will have to be
cranked rather fast in most cases in order to get a sufficient
current strength to have the current jump the gap at the spark
plug. In fact, it may be necessary in many cases to turn the
engine crank over several revolutions as fast as can be done
by hand in order to get a sufficiently high armatiu-e speed to
produce sparks at the spark plug.

When the ignition is furnished by a synchronous magneto
that gives a much weaker current when the spark is retarded
than when fully advanced, the engine can rarely be started
on the magneto with the spark retarded, as it cannot be cranked
fast enough to get up an armature speed sufficiently high to
give a spark at the spark plugs. It will usually be necessary
to advance the spark lever to about the middle of the spark
range, and sometimes even more, with the attendant risk of a
back-fire. Since magnetos of the type under discussion are,
in practice, almost invariably used in connection with either
dual or double ignition systems, it is the usual practice to

Digitized by

Google

82 ELECTRIC IGNITION §8

employ the battery system for starting the engine and to change
over to the magneto system after the engine has been started.
With some magnetos of the type imder discussion, it is neces-
sary to change over to the battery system when the engine is
running slowly, driving the car on high gear, because the arma-
ture speed is then insufficient to produce a spark.

MBTHOD OIVINO SPABK VARIABLE OVER MAGNETO SPABK

RANGE

31. In many magneto ignition systems, the advance and
retard of tjie spark is obtained by rotating either the inter-
rupter lever or the cam, depending on which part is fixed to the
armature shaft, in relation to both the armattire and field mag-
nets. For instance, if the interrupter leyer or mechanism is
fitted to the end of the armature shaft and is turned by it,
the cam is generally arranged so that it can be rotated back-
wards and forwards. When it is moved in the direction of
rotation of the armature, the time at which the primary cir-
cuit is broken is made later and the spark is retarded; if it is
moved in the opposite direction, the spark is advanced. In
case the cam is fixed to the end of the armature shaft, the
advance and the retard are accomplished by rotating the inter-
rupter lever. When this lever is moved in the direction of
rotation of the armature, the time of interruption of the cur-
rent is made later and the spark retarded; when it is moved
in the opposite direction, the spark is advanced.

32. With a magneto having two pole pieces and the usual
form of shuttle armattire, irrespective of whether the magneto
is of the low-tension or the high-tension type, the maximum
electromotive force is produced in the primary circuit at two
diametrically opposite points in the revolution of the armattire,
in which case the best spark is obtained at the spark plug when
the primary circuit is broken at these points. Magnetos are
tisually set so that the maximum spark is obtained when in the
advance position, for this position is the one that is used most.
But, with a magneto in which the primary circuit-breaking
mechanism can be rocked in relation to both the annatiu^ and

Digitized by

Google

§8 ELECTRIC IGNITION 83

fidd magnets, as just explained, the spark will be weaker as it
is retarded, because the break in the primary circuit will not
occur when the current is at the point of maximum intensity.
On this account, such a magneto, provided the speed of the
armatiu^ is the same in each case, will not produce so good a
spark when in the retard position as when in the advance
position.

METHODS OIYINO SPABK UNIFORM OVEB MAGNETO SPABK

RANGE

33. Classification. — Many methods have been devised
for use in connection with synchronous magneto ignition sjrs-
tems whereby it is possible to obtain a spark of tmiform, or
practically uniform, intensity dimng the entire range of spark
control, from full advance to full retard. Among these methods
the most important are the following:

1. By rocking the field magnets, keeping the one part of the
interrupter mechanism fixed in relation to the field magnets
and the other part fixed to the armature. Either the inter-
rupter lever, or its equivalent, or the interrupter cam may be
fixed in relation to the field magnets.

2. By making use of a movable n^ignetic screen that is
located between the armature and the field magnets, and to
which one part of the interrupting mechanism is attached.

3. By making use of a coupling in the armature shaft, by
means of which the armature n^iy be rotated in relation to the
engine. Either the interrupting mechanism is rotated with the
armature and the cam is held stationary in relation to the field
magnets, or the cam is rotated with the armature and the
interrupting mechanism is held stationary in relation to the
field magnets.

4. By the use of either extended or specially shaped pole
pieces.

84. Hocking Field Magnets. — ^A unique method of
obtaining a spark of the same intensity in the retard position
as in the advance position consists in rocking the field magnets
of the magneto with one part of the interrupter, the second part

Digitized by

Google

84 ELECTRIC IGNITION § 8

of the interrupting mechanism being attached to the armattire
shaft and rotating with it in the usual manner. It is well to
bear in mind that the interrupter or the circuit-breaker mechan-
ism consists essentially of two parts, namely, an interrupter
cam of suitable form and an interrupter lever or equivalent
mechanism carrying a contact screw; the cam, by lifting the
lever, breaks the primary circuit, thus interrupting the primary
current formed by the primary winding of the magneto arma-
ture. Obviously, either the interrupter lever or the inter-
rupter cam may be rigidly attached to the armature.

36. The effect of keeping one part of the interrupter in
the same position with reference to the magnets, and the other
part in the same position with reference to the armature, is
illustrated diagrammatically in Fig. 9. As shown in this illus-
tration, the interrupter lever a is hinged to one of the magnet

Fig. 9

pole pieces 6, and the two-lobed cam c is rigidly attached to the
armature. In a shuttle-woimd armature, the maximimi cur-
rent occurs when the armature core d. Fig. 9 (a), is in the posi-
tion at which the end pieces of the core section bridge the gaps
between the pole pieces, as shown. It is therefore necessary
that the primary current always be interrupted at this point
in the rotation of the armature in order to obtain a spark of
maximimi intensity for all positions of advance and retard.
This is accomplished when the interrupter parts are fixed with
respect to the magnets and armature, and the magnets are
rocked to advance and to retard the spark.

Assume that the magnets, and, hence, the pole pieces 6,
view (6), and also the one part of the interrupter, are rocked
in the direction of the arrow x, which is opposite to that in

Digitized by

Google

§ 8 ELECTRIC IGNITION 85

which the armatiire rotates, as shown by the arrow y. Inas-
much as the cam c is fixed to the armature, the primary current
is broken when the armature core is in the position shown in
view (a); that is, at its point of maximum intensity. Also,
since the armattu^e is positively driven by the engine, the bi cak-
ing of the primary circuit occurs earlier with reference to the
stroke of the piston; that is, the spark is advanced by rocking
the magnets and one inter-
rupter part in a direction
opposite to that in which the
armature rotates.

If the magnets and the one
interrupter part are rocked in
the direction in which the ar-
mature rotates, as in view (c),
the breaking of the primary
current occtirs later with refer-
ence to the piston stroke; that
is, the spark is retarded.

36. Movable Magnet J c

Screen. — ^Virtually the same

effect that is obtained by the

use of movable field magnets

may be secured by means of

a movable screen, or shield,

, . , ; J^'G. 10

located between the armature

and field magnets of the magneto. In such a construction, one
part of the interrupting mechanism is attached to the screen
and rocked with it when the spark is advanced or retarded.
The screen is usually made of soft iron or steel. Rocking it
between the pole pieces and armattu"e has the effect of shifting
the magnetic field; but, as one part of the interrupting mecha-
nism and the screen, or field, are always in the same relative
position, a current of the same intensity throughout the entire
range of spark control is obtained.

37. The magnetic screen, as applied in practice to a mag-
neto, is illustrated in Fig. 10, which shows a cross-sectional

Digitized by

Google

ELECTRIC IGNITION

§8

view of the Pittsfield high-tension magneto. The field of the
magneto contains four poles, so that the screen is n^ide up of
four iron bars a, which, together with the interrupting mecha-
nism, are moimted on suitable heads.

38. In Fig. 11 is shown the effect of rotating the n^ignetic
screen with one part of the interrupting mechanism, when
advancing or retarding the spark, as appUed to a two-pole
magneto. The screen is composed of two pieces of iron a
and b located between the shuttle-woimd armatiire c and the
pole pieces d and e. The maximimi current is generated when
the end pieces of the core section of the armature bridge the
gaps between the parts of the magnetic screen, as is shown in
view (a). The interrupter lever / is hinged to the screen, and
the two-lobed cam g is attached to the armature and rotates

Pig. 11

with it. When the movable screen, together with the inter-
rupter arm/, is rotated in the direction indicated by the arrow x,
or opposite to the direction in which the armature is turning,
as indicated by the arrow y, it assumes the position shown in
view (6) and the spark is advanced in the manner explained in
Art. 35. As the cam is fixed to the armature, the primary
circuit is broken when the magnetic screen and the armature
are in the relative positions shown in view (a), or when the
maximum current is being generated.

When the spark is retarded, the magnetic screen and the
interrupter arm are rotated in the same direction in which the
armature is turning, and they assume the position shown in
view (c). As the screen and the armature keep the relative
positions shown in views (a) and (6), the maximum current,
practically speaking, is also generated for a retarded spark;

Digitized by

Google

§8 ELECTRIC IGNITION 87

thus, the highest electromotive force is produced for all settings
of the spark advance.

39. Armature Sliaft Couplings. — One form of shaft
coupling by means of which the armature and the interrupting
mechanism of a magneto are advanced or retarded so as to
obtain a current of uniform intensity for all settings of the
spark is described in Art. 13 and illustrated in Fig. 3, in con-
nection with the Eisemann automatic governor. It consists
principally of two parts, namely, a guide, which is fixed to the
armature, and a nut, or sleeve, containing helical grooves that
fit over corresponding threads on the drive shaft of the magneto.
The sleeve is free to slide in the guide; therefore, when it is
moved toward the armature, it advances the armature and inter-
rupting mechanism in relation to the drive shaft and thus
advances the spark, and when it is moved away from the arma-
ttu"e it retards the spark. In the Eisemann magneto the sleeve
is moved automatically by the centrifugal action of the gov-
ernor weights. Similar couplings are sometimes used where the
spark is controlled by hand, in which case the sleeve is operated
from the hand lever on the steering wheel. Either the inter-
rupting mechanism or interrupter cam may be attached to the
armature and advanced or retarded with it in order to vary
the time of ignition; and if the second part of the interrupter
is kept stationary with respect to the magnets, a spark of
tmiform intensity will be obtained over the whole spark range.

40. Special Pole-Piece Construction. — Specially shaped
pole pieces, such as are illustrated in Fig. 12, are sometimes
used on magnetos for the purpose of giving a current of
electricity with an intensity that is high enough to produce
a good spark in the retard position and at low engine speeds.
In some cases the pole pieces are extended and notched, or
provided with teeth, and in other cases they are pointed in the
middle.

41. When the pole pieces of a magneto are extended and
notched, as illustrated in Fig. 12 (a), two regions of maximimi
intensity of the lines of force are produced. The first region
is at the notch a and the second at the edge b of the pole piece.

Digitized by

Google

88 ELECTRIC IGNITION § 8

The effect of the notch a is to intensify the lines of force at this
point; thus, as the armattire passes it, there is a change in the
nmnber of Unes of force cut and a current is produced. In a
similar manner, a current is generated when the armature

passes the edge b of the pole pieces.
The magneto may be set so that a
spark occurs in the adyance position
when the armature passes the notch a,
and in the retard position when it
passes the edge b. This produces a
current of approximately uniform in-
tensity for all positions of the spark
advance from full advance to full re-
tard. This form of pole piece is used
in some models of the Simms magneto.

42. Where the pole pieces of a
magneto are extended and provided
with teeth, as shown in Fig. 12 (fc), the
greatest change takes place in the num-
ber of lines of force cut by the arma-
ture when it passes the roots c of the
teeth and when it passes their ends d.
Therefore, as the highest electromotive
force is produced when the armature
coils pass these points, the magneto
may be set to produce a spark in the
advance position when the edge of
the armature passes the roots of the
teeth and in the retard position when
it passes their ends. Pole pieces of
this form are used in several models
of the Bosch magneto.

43. Pole pieces are sometimes
, as is illustrated at e, Fig. 12 (c). The
:^tion is to draw the lines of force toward
le pieces and thus intensify the field at
Jt is that the intensity of the induced

Digitized by

Google

§ 8 ELECTRIC IGNITION 89

current is increased and a hotter spark is formed at the spark
plug. Pole pieces shaped in this manner are used in some of
the Eisemann magnetos.

STARTING ON THE SPAKK

RBQUIBEAIENTS

44. An automobile engine is said to be started on the spark,
or on compression, when it is set in motion by opening or closing
the primary circuit of the ignition system by hand, and thus
producing a spark in the cylinder whose piston is at that time
on its working stroke. In order to start an engine on the spark,
it must be stopped with a combustible mixture in one of the
cylinders and with the piston in that cylinder on its working
stroke, so that when the spark is formed it will fire the charge
and drive the piston forwards and thus start the engine. To
produce a spark with the engine stopped, the ignition system
must be equipped with either a dry-cell battery or a storage
battery in order that current will always be available. An
automobile equipped with a magneto only cannot be started
on the spark, because no current can be obtained, and hence
no spark produced, with the engine and magneto not running.
It follows, therefore, that in order to be started on the spark,
automobiles must be fitted either with a single battery system',
a dual system, or a double system, each of which employs a
battery.

METHODS OF STARTTNO ON THE SPARK

46. When an automobile is fitted with a single battery
system and vibrator coils, the engine is started on the spark
by placing the spark advance lever in the retarded position
and then closing the hand switch in the primary circuit. If
the primary circuit happens to be closed at the timer, by the
closing of the hand switch, the vibrator is set in motion, and
a high-tension current is induced in the secondary winding
of the induction coil. This current is led to the spark plug

222B— ^

Digitized by

Google

90 ELECTRIC IGNITION §8

in the proper cylinder by the secondary cable, and if the cylin-
der contains a compressed charge it is fired with the desired
result. The arrangement of the ignition system is such that
the rotor of the timer is always in contact with the contact
piece connected to the coil that is in the circuit of the cylinder
whose piston is about to begin, or is on, its working stroke.
This insures a spark in the proper cylinder.

In case the system is provided with a single coil and a dis-
tributor, a spark will be produced in the cylinder only when
the rotor of the distributor is in contact with the contact
segment leading to that cylinder. If the engine has stopped
with the distributor rotor between two of the contact segments,
or brushes, no high-tension current will be produced, because
the secondary circuit will not be complete; hence, an engine
cannot be started on the spark imder these conditions.

46. Starting on the spark with a dual ignition system
employing a magneto and a battery with a non-vibrator coil
is effected by moving the switch to the battery position and
then pressing a button, which either breaks the battery circuit
momentarily or brings into the circuit a vibrator, thus changing
the coil to a vibrator coil for the time. When, by pressing the
button, the battery circuit is broken only momentarily, a
single spark is formed; but, when a vibrator is brought into
action, the circuit is broken a number of times and a series
of sparks is produced. With the dual sjrstem, in which the mag-
neto distributor is also used for the battery system high-tension
cturent, the rotor of the distributor must be in contact with
one of the brushes leading to a spark plug in order to have a
spark produced in the cylinder. Obviously, in order to pre-
vent a back-fire, the spark lever should be in its retarded
position.

47. With the double system of ignition, which consists
of two entirely independent systems, one receiving current from
a magneto or dynamo and the other from a battery, the engine
may be started on the spark by making use of the battery
current, either as in the single battery system or as in the dual
system.

Digitized by

Google

§ 8 ELECTRIC IGNITION 91

MODERN IGNmON SYSTEMS

SINGLE MAGNETO IGNITION SYSTEMS

CLASSIFICATION

48. A single magneto ignition system is one contain-
ing but a single source of electric current, that source being a
magneto. In such a system, all the current used for ignition
purposes is obtained from the n^igneto, and no battery is con-
nected in the circuit. The magneto used may be either a low-
tension magneto generating a current of low voltage and requir-
ing the use of a separate vibrator or non-vibrator induction
coil, or a high-tension magneto generating a ctirrent of sufficient
voltage to jump the gap in the spark plug and thus form a spark
without the aid of a separate coil.. A single magneto ignition
system employing a low-tension magneto may be called a low-
tension single magneto system^ and one employing a high-tension
magneto may be called a high-tension single magneto system.

49. In a low-tension single magneto ignition system, the
source of current is a magneto of the low-tension type, as just
explained. Such a magneto generates a current of insufficient
electromotive force to cause a spark to jump the air gap in the
spark plug, so that separate vibrator or non-vibrator induction
coils must be used to change this low-tension current into cur-
rent having the necessary voltage. Where non-vibrator induc-
tion coils are used, the magneto must run in synchronism, that
is, in step, with the engine, so that the spark occurs when the
current is most intense, or, twice during each revolution of
the armature in the common shuttle-wound type of magneto.
When a vibrator or a trembler coil is used, an alternating- cur-
rent nMigneto need not rotate in synchronism with the engine;

Digitized by

Google

92 ELECTRIC IGNITION §8

but it must rotate at a suflSciently high rate of speed in order
that the alternations of the current will be so rapid that but
little variation in the electromotive force will occur at the
instant of ignition. This latter type of magneto is known as a
high-frequency alternating-current magneto.

60. The high-tension single magneto ignition system differs
from the low-tension single magneto system in that the cur-
rent is supplied by a high-tension magneto that generates a
current of sufficiently high voltage to jump thc^ gap in the spark
plug, and hence no separate induction coils are required. This
ignition system is the simplest one in tise, because the out-
side wiring consists only of the secondary cables running
from the magneto to the spark plugs, and the primary wire
running from the magneto to the switch on the dash, by
means of which the magneto may be grounded and the ignition
thus cut out.

In order that a high-tension magneto can be used to furnish
current for a single ignition system, it is desirable that it be
so constructed as to give as effident a spark in the retard posi-
tion as in the advance position. Any high-tension magneto
so constructed that a good spark can be obtained by cranking
with the control in the retard position is especially suitable
for supplying current to a single ignition system.

LOW-TENSION SINOLB MAGNETO SYSTEM

51. Construction of Ford High-Frequency Magneto.

A well-known example of the high-frequency alternating-cur-
rent magneto is that used on the Ford Model T automobile.
Fig. 13 (a) shows this magneto assembled in the case with part
of the planetary transmission system. The magneto consists
essentially of a stationary armature containing sixteen spool-
shaped coils a attached to a spider that, in turn, is atttached
to the cylinder casting, and a set of the same nvimber of per-
manent horseshoe magnets b fixed to the fljrwheel and rotating
with it. The magneto is therefore direct-connected to the
engine and is located at the rear end of the crank-case.

Digitized by

Google

§ 8 ELECTRIC IGNITION 93

One of the armattire coils is shown in detail at a, view (6).
Each coil has two windings of copper-ribbon wire, one winding
being clockwise, and the other counter-clockwise. The coils,
which are arranged at equal intervals around the armature
plate d, are connected in series with each other, the two ter-
minals being brought out at the top of the casing. One of the
terminals is connected by means of a spring connection to a
binding post on top of the magneto and the other terminal
is groimded on the armature plate. At fc, view (6), is illustrated
one of the horseshoe magnets, sixteen of which are spaced
aroimd the flywheel c, as shown in view (a). The magnets are
set with the closed ends next to the center of the fljrwheel and

Pig. 13

with the poles extending outwards and Opposite the coils. In this
arrangement, two north poles are placed together and two south
poles are placed next to each other. The magnets revolve
with the flywheel and at a distance of yy inch from the station-
ary coils, so that a magnetic field is set up about the coils and
a current is induced in them. The current generated in the
armature coils flows, by way of the binding post, through the
induction coils and back through the engine frame and magneto
frame to the groimded terminal on the armature plate, thus
completing the circuit.

As the magnets move through a large circle, they have a
high peripheral speed in relation to the rotary speed of the

Digitized by

Google

94 ELECTRIC IGNITION §8

engine. On account of this, a good spark may be formed by
hand-cranking, for the magnets pass the coils at a comparatively
high rate of speed even when the engine is turned over slowly.

52. wiring Diagram for the Ford Magneto. — ^The
method of wiring the Ford low-tension magneto system of
ignition is illustrated in Fig. 14. This illustration shows the
front part of the automobile with part of the hood and the dash

Pig. 14

removed, exposing the engine cylinders a and coil box 6. As
will be observed, the coil box is located on the side of the dash
next to the seat. It contains four induction coils with either
individual vibrators or a master vibrator, there being one coil
for each cylinder. Low-tension current is taken from the
magneto at the binding post c and flows through the wire d
to the primary terminal e of the induction coils. It then flows
through the primary winding of the coil, which, at that instant,
is connected in the circuit by the timer /, through the proper

Digitized by

Google

§ 8 ELECTRIC IGNITION 95

wire to the contact piece of the timer, and then back to the mag-
neto by way of the timer rotor and engine frame. For instance,
assume that the rotor of the timer is in contact with* contact
piece number 1. The primary current then flows through
the primary winding of coil nvimber 1, through the proper
connection to the contact piece nvimber 1 of the timer, and back
to the nMigneto by way of the ground. While the current is
flowing through this path, the vibrator of coil number 1 is
rapidly opening and closing the primary circuit, so that a cur-
rent of high tension is induced in the secondary winding of
that coil. This current flows through the high-tension cable g
to the spark plug number 1 and then back to the secondary
winding of the coil by way of the engine cylinders and frame and
rotor of the timer, completing the circuit through part of the
primary circuit, as is the case in three-terminal coil systems.
The timer connections in this system are such that the order
of firing is 1-2-4-3.

The Ford magneto ignition sjrstem, although classed as a
single magneto system, is so arranged that it can be readily
changed into a dual system by connecting up a battery so that
it can be used to supply current in place of the magneto. The
induction coils are provided with a binding post for connecting
one terminal of the battery into the system, the second battery
terminal being grounded to the frame. The connections to the
switch regularly furnished on the coil box are such that, with a
battery connected up in this manner, the regular switch n^iy
be used for cutting out the magneto and connecting the bat-
tery in the circuit without any other change being made in the
system. The battery binding post is shown on the coil box at fc,
Fig. 14. When the battery is used for ignition in the Ford car
the battery current is entirely independent of the magneto,
but it uses the same timer as the magneto.

HIOH-TENSION SINGLE MAONETO SYSTEMS

53. Construction of the Mea Hlgh-Tenslon Magneto.

An example of a high-tension magneto designed for use with the
single ignition system is the Mea magneto, one model of which

Digitized by

Google

96 ELECTRIC IGNITION § 8

is illustrated in Figs. 15, 16, and 17, like parts being lettered
the same in these illustrations. The complete magneto is
shown in Fig. 15. It is provided with rocking field magnets a,
which are illustrated in detail in Fig. 16, so that the magnets

and armature are
always in the same
relative positions
when the spark oc-
curs, and a spark of
imiform intensity is
therefore produced for
all positions of ad-
vance and retard.
The magnets are bell-
shaped and arranged
horizontally in the
magneto, with the ar-
mature shaft extend-
^*°' ^^ ing through a hole in

the closed end. The entire magneto is mounted in a frame 6,
Fig. 15, and the time of ignition is varied by rocking it by
means of the control arm c,

54. On referring more particularly to Fig. 17, which is a
longitudinal section and end view of the magneto, it will be
seen that the armature d, the winding on which consists of a
few tiuTis of a heavy primary winding ^^spb^b-^bii^^*^
and many turns of a fine secondary iKo^^^^^^^^

winding, is carried by the ball bear- ^ ^ ^k

ings e and /, upon which the shaft g ^^^^^^^^j^BH
rotates. The shaft g also carries the ik^— .5=^B^W|^r
interrupter, which revolves with the ^SSBJ^^B/I^

armature and is composed of the ^ ,^

. . 1 Pig* 1^

roller fc, the sprmg ;, and the contact

points k and /. A cam-disk m is fixed to the magnets, and
carries two cams located opposite each other. As the roUer h
passes over the cams, it presses against the spring ; and sepa-
rates the contact points k and /. A current is therefore induced

Digitized by

Google

Digitized by

Google

ELECTRIC IGNITION

§8

in the secondary winding twice during each revolution of the
armattu-e. The condenser n is connected in the primary circuit
to prevent the interrupter contact points from btiming and to
help increase the voltage of the secondary current. The high-
tension current is collected from the collector ring o by means of
the brush p set into the brush holder q, and is carried to the
distributor r through the bridge s. From the distributor, the
current is led in the regular way through the secondary ter-
minals to the spark plugs. A safety spark gap is provided at t
to protect the armature from excessive voltages in case the
plugs become disconnected or the spark plug gap becomes too

Pig. 18

wide. A good groimd between the armatiu-e and the rest of
the magneto is insured by means of a carbon grounding brush u.
The Mea magneto can be driven only in one direction; if
the armattu^ is to rotate in an opposite direction, a new cam-
disk arranged for this direction must be substituted for the old ^
cam-disk of the interrupting mechanism.

55. Principle of Operation of the Mea Magneto. — ^The
principle of operation of the Mea high-tension single magneto
system of ignition is shown in Fig. 18, which is a diagram of
connections for this system arranged for a four-cylinder engine.
A low-tension current is generated in the primary winding d

Digitized by

Google

§ 8 ELECTRIC IGNIt ION 99

by the rotation of the
armature between the
magnets of the magneto.
This current flows to
the interrupter a by way
of the long screw that
holds the interrupter in
place, and from this point
it flows back to the ar-
mature through the
frame of the magneto
and armature core to
which the primary wind-
ing is attached. When
a charge is to be fired,
the low-tension current is
interrupted by the inter-
rupter a and a high-ten-
sion current is induced
in the secondary wind-
ing b. The high-tension
current is carried to the
distributor c through the
internal connections of
the magneto and is di-
rected to the spark plugs
in the proper order,
which, in this case, is

66. wiring Dia-
gram for tlie Mea
Magneto. — A wiring
diagram that illustrates
the outside connections
of the Mea high-tension
single ignition system is
shown in Fig. 19. The

Digitized by

Google

100 ELECTRIC IGNITION § 8

low-tension terminal M of the magneto is connected by a
primary wire to one terminal of the switch S located on the
dash of the automobile. The other terminal of the switch is
connected to the frame of the car or engine, as at (J, so that the
primary current may be grounded and the ignition cut out
by closing the switch. The distributor terminals ly Sy S, and 4
are connected to the proper spark plugs by the secondary
cables in order to give the desired order of firing. The order
of firing shown in the diagram is 1 -8-4-2 y so that distributor
terminal 1 is connected to spark plug 1 ; terminal 2y to spark
plug 8\ terminal 5, to spark plug 4\ and terminal ^, to spark
plug^.

57. Bosch High-Tenslon Magneto. — ^Another high-ten-
sion magneto, one model of which is designed to be used with

the single system of ignition, is
the Bosch magneto. An outside
view of the single ignition, or
independent, magneto is shown
in Fig. 20, and a longitudinal
section and an end view of the
same magneto are shown in
Fig. 21. This type of magneto
differs from another model of the
Bosch magneto in that the arma-
ture, instead of being stationary,
^'^* ^ is a double-wound armature of H

section revolving between horseshoe magnets. Extended pole
pieces having the extensions cut into broad teeth are employed
on this magneto, so that a hot spark may be obtained with the
spark control set in the retard position as well as in the advance
position, thus providing a safe way for starting the engine by
hand cranking.

58. Referring to Figs. 20 and 21, in which like parts are
lettered the same, one end of the primary winding is grounded
to the armature core, and the second end is connected to
the brass disk a. A fastening screw b passes through the
disk a, holding the interrupter in place and also conducting

Digitized by

Google

§ 8 ELECTRIC IGNITION 101

the primary current to the interrupter contact-block c. The
screw b and the block c are insulated from the interrupter
disk dy which is electrically connected to the armature core.
The interrupter contact-block c carries a platinimi contact

screw fitted with locknuts. The interrupter lever e is in the
form of a bell-crank, and carries on one end a platinum screw
that makes contact with the one in the block c and is held
in contact by means of a spring. The interrupter lever is

Digitized by

Google

102

ELECTRIC IGNITION

§8

electrically connected to the armature core and, hence, to one
end of the primary winding, which is thiis short-circuited as
long as the platinum screws of the contact-block and interrupter
are in contact. The interrupter housing / can be rocked to
advance or retard the spark; it carries two steel cams that,
through coming in contact with the one end of the interrupter
lever e, break the contact between the screws of the inter-
rupter lever and contact-block c, thereby suddenly breaking
the primary circuit. A condenser h is electrically connected
in a shunt across the two contacts of the interrupter mechanism.
The secondary winding is placed directly over the primary

Pic. 22

armature winding, one end of the secondary winding being
connected to the live end of the primary winding and the other
end to the slip ring i. A carbon brush ; conducts the high-
tension current to the carbon brush k of the distributor rotor.
The distributor disk / is stationary, and has embedded in it
foiu* metal segments m (for a fotu'-cylinder engine) that con-
nect electrically with terminals to which the spark-plug cables
are attached. A safety spark gap n is placed in the high-tension
circuit.

The purpose of the terminal ^ is to connect the primary cir-
cuit to a switch, through which the magneto may be grounded.

Digitized by

Google

§8

ELECTRIC IGNITION

103

59. The internal connections for the Bosch magneto are
shown in Fig. 22. The low-tension current generated in the
primary winding a of the magneto is carried to the inter-
rupter 6, where it is interrupted twice during each revolution
of the armature. From this point, the current returns to the
armature by way of the frame of the magneto. The high-
tension current, which is induced in the secondary winding c,
is carried to the rotor d of the distributor e, from which it is
sent to the spark plugs through the contact pieces l,2,Sy and 4,
The secondary current returns to the secondary winding by
way of the cylinder walls and engine frame, thus completing
the circuit.

60. wiring Diagram for the Boscli Single System.

The outside wiring connections for the Bosch single ignition
system for a four-cylinder engine are practically the same as
those previously shown in connection with the Mea magneto.
The wiring diagram is shown in Fig. 23. The primary ter-

Pig. 23

minal M of the magneto is connected by a primary wire to a
terminal of the switch S on the dash. The other terminal of
the switch is grounded on the frame G of the automobile,
thus providing a means of grounding the magneto and cutting
out the ignition. The high-tension distributor terminals

Digitized by

Google

104 ELECTRIC IGNITION § 8

ly 2, S, and 4 are connected to the different spark plugs in the
proper order to secure the firing order desired. In Fig. 23,
the firing order 1-2-4-3 is shown. This is obtained by con-
necting distributor terminal 1 to spark plug 1, distributor ter-
minal 2 to spark plug 2, terminal 3 to spark plug ^, and
terminal 4 to spark plug 3. The other firing order, which is
1-3-4-2, for a four-cycle engine, may be obtained by making
the proper connections.

DUAL IGNmON SYSTEMS

DEFINITIONS

61. A dual system of ignition is one that contains two
separate and distinct soiu*ces of electricity, either of which may
be used to supply current to a single set of spark plugs. The
two sources of current ordinarily consist of a magneto and a
battery, each of which is connected to a switch on the dash of
the automobile, so that either may be brought into the ignition
circuit. Either a low-tension magneto requiring a separate
transformer coil or a high-tension magneto may be used in
connection with the battery in a dual system. When a low-
tension magneto is used with a battery, the same transformer
coil and primary current interrupter are usually employed by
both the magneto and the battery; but, when a high-tension
magneto and a battery are used, a separate coil for the battery
current must be connected in the circuit, and a separate bat-
tery interrupter is sometimes provided. In either case, the
distributor and secondary wiring are common to both the
magneto and the battery. Either a dry-cell battery or a
storage battery may be used in the dual system of ignition.

LOW-TENSION DUAL MAONETrO SYSTEM

62. Construction of Magneto. — An example of a widely
used dual system of ignition employing a low-tension magneto
as one of the soiu*ces of current is the Splitdorf system. In this
system, the magneto is of the ordinary low-tension type,

Digitized by

Google

§ 8 ELECTRIC IGNITION 105

containing an armature with a single winding so that a current
of low voltage is generated. One model of this magneto is
illustrated in Figs. 24 and 25, Fig. 24 being an external view
and Fig. 25 an end view and longitudinal section. Reference
to these illustrations, in which like parts are lettered the same,
will show that the single-wound armature a, which rotates
between the poles of the magnets c, is driven by the shaft h car-
ried on ball bearings d and d'. The insulated plug e carries the
generated current from the armature to the terminal /, from
which it is led to the transformer coil. The interrupter g,
shown in detail in
Fig. 25, is composed
of a two-lobed cam fc,
which is mounted on
the sleeve ; and ro-
tates with the arma-
ture, and a lever k,
A longitudinal section
of the sleeve ; is shown
in the sectional view.
The lever is raised by
the cam, which serves
to break the circuit by
separating the contact

points at /. The time ^'''- ^*

of ignition is varied by rocking the arm x, which rotates the
lever k in relation to the position of the cam and armature.
The distributor m is driven from the armature by the gears n
and 0.

63. Principle of Operation. — ^The inside wiring con-
nections for the Splitdorf dual system of ignition are indicated
in Fig. 26. In this illustration, the magneto armatiu*e is shown
at a, the battery at 6, the switch at c, the transformer coil at d,
the interrupter at e, the condenser at/, the distributor at g, and
the spark plugs at h. With the switch blade / in the position
indicated by the full lines, the magneto supplies the current
and the battery is cut out of the system. With the magneto

222B— 31

Digitized by

Google

106

Digitized by

Google

§ 8 ELECTRIC IGNITION 107

thus connected in the circuit and the interrupter points closed
as shown, current flows from the armature a to the switch
terminal M, then through the blade / to the terminal M\
and back to the magneto through the interrupter and ground.
The current at this instant does not flow through the trans-
former coil, but is short-circuited. However, the moment that
the lobe of the cam strikes the interrupter lever, the short
circuit is broken and the current flows from the center of the
switch blade through a metallic connection k to the terminal B'
and thence to the primary winding of the induction coil. The

Pig. 26

circuit is completed back to the magneto armature through
the primary-secondary terminal ps and the ground. The
sudden increase of current in the primary winding of the coU,
caused by separating the interrupter points, induces in the
secondary winding a high-tension current of sufficient voltage
to jtunp the gap in a spark plug and produce a spark. This
secondary current flows to the distributor by way of the ter-
minal 5, and is transmitted to the spark plugs in the desired
order and returned to the induction coil through the ground
connections.

Digitized by

Google

108 ELECTRIC IGNITION § 8

With the switch blade in the battery position, as indicated
by the dotted lines /^ the magneto circuit is broken and the
battery is connected in the system. It is to be noted that while
the switch blade makes contact with the terminal B when in
this position it does not make contact with B\ so that the bat-
tery circuit is completed through the switch by ;means of the'
connection k. In this case, when the interrupter points are
closed, the current flows from the battery to the primary ter-
minal p on the coil by way of the switch blade ;' and the con-
nection k. After passing through the primary winding, it
returns to the battery through the ground and the interrupter.
When the battery circuit is broken at the interrupter, a high-
tension current is induced in the secondary winding of the
induction coil on account of the sudden decrease of current
in the primary winding. This high-tension current is trans-
mitted to the spark plugs by the distributor in the regular
manner.

It is well to remember that in the Splitdorf dual system the
battery cannot have one terminal groimded to the frame of
the car; both battery terminals must be connected to battery
binding posts provided on the coil box.

64, By tracing the magneto and battery circuits in the
manner just described, it is evident that when the magneto is
used the high-tension current is obtained by interrupting
the short-circuit of the primary current, but when the battery
is in use the secondary current is formed by interrupting the
primary current. Thus, two distinct methods of inducing
a secondary current are employed in this system, one in con-
nection with the magneto current and the other with the battery
current.

65. An engine using this system of ignition is started on
the spark by pressing a push button that controls the connec-
tion k in the switch. When starting on the spark, the circuit
must be closed at the interrupter and the distributor rotor must
make contact with one of the distributor terminals. A spark
can then be produced in the spark plug connected at that instant
to the distributor by putting the switch in the battery position

Digitized by

Google

§8 ELECTRIC IGNITION 109

and pressing the button. This operation breaks the battery
circuit and induces in the secondary winding of the induction
coil a high-tension current that is of sufficient voltage to form
a spark at the spark plug.

66. Wiring Diagram. — ^The practical wiring diagram for
the model T SpUtdorf low-tension magneto with a transformer
coil is shown in Fig. 27. With the switch handle e in the mag-
neto position, current flows from the magneto terminal a to
the transformer terminal a', and then back to the magneto by
way of terminals V and 6 or c' and c, depending on whether
the interruptei* points are closed or open. In case the inter-
rupter points are closed, the primary current returns to the

Pig. 27

magneto armatiu*e through the wire V b and the interrupter;
but, if they are separated, it rettuns through the wire c' c and
the frame of the magneto.

When the switch handle is in the battery position, the mag-
neto circuit is broken and the battery circuit completed through
the interrupter by means of connections 6' b and c' c. In the
oflf-position, the switch blade does not make contact with any
terminal, so that both the magneto circuit and the battery
circuit are cut out. The secondary current that is generated
in the secondary winding of the coil is transmitted to the

Digitized by

Google

no ELECTRIC IGNITION §8

distiibutor terminal d from the transformer terminal d\ From
the distributor it is led to the spark plugs by the high-tension
cables, as shown. The order of firing depends on the arrange-
ment of the high-tension cables, that illustrated being 1-3-^-2.

HIOH-TENSION DUAL MAONETO STSTEliS

67. Construction of the Bosch Dual Magneto. — ^With
the exception of a few minor details, the magneto used in the
high-tension dual magneto ignition system is the same as that
used in the single high-tension magneto system, a current of

Pig. 28

liigh voltage being generated in exactly the same manner.
The only difference in the construction of the high-tension dual
magneto and the single ignition, or independent, magneto
is that the former is provided with an additional interrupter
for timing the battery circuit and a secondary terminal for con-
necting the high-tension distributor to the switch on the bat-
tery coil, the direct connection between the collecting ring and
distributor being removed.

68. Fig. 28 shows the Bosch high-tension magneto equipped
for dual ignition, the interrupter cover e being removed so as

Digitized by

Google

§ 8 ELECTRIC IGNITION 111

to show the parts of the interrupters. When thus equipped
the conductor between the collecting ring and distributor is
removed and a central terminal a is added to the distributor
for the purpose of connecting it, by means of a wire, to the
switch. This is done so that the current will flow to the dis-
tributor by way of the switch when the magneto is connected
in the circuit. The other featiu*e of this magneto is the addi-
tion of the battery timer or interrupter. This consists of the
interrupter lever 6, the contact points c and d, and a two-lobed
cam, not shown in the illustration. The cam is attached to
the magneto interrupter disk and rotates with the armattu-e.
It is in the form of a steel ring carrying two lobes, or projec-
tions, that rock the lever b as they pass it, thus opening and
closing the battery circuit of which the lever forms a part.
The time of ignition is varied by rotating the timer mecha-
nism by means of the control arm /. The interrupter lever b
is electrically connected to the frame of the magneto, but the
other parts of the mechanism are insulated from the remainder
of the magneto.

69. Wiring Diagram for the Boscli Dual System.

The wiring diagram for the Bosch dual system of ignition
is illustrated in Fig. 29. In view (a), the high-tension mag-
neto is shown at A, the battery at B, the spark plugs atC, and
an end view of the combined spark coil and switch at -D, illus-
trating the connections at the switch. In view (6), this coil is
shown in place on the dash of the automobile. Either the mag-
neto or the battery can be connected in the circuit by means of
the switch that is operated by the handle /. When the handle
is moved, the entire coil within the housing is rotated and
the desired connections are made on contact plates by means of
spring contacts. For instance, when the handle is moved to the
battery position, the battery circuit is completed. It extends
from the battery terminal g to the switch terminal g', through
the primary winding of the coil and, by way of the switch
terminal h\ to the battery interrupter h on the magneto. From
the battery interrupter it flows by way of the magneto frame
and ground connection /' back to terminal ; on the battery.

Digitized by

Google

112 ELECTRIC IGNITION § 8

At the same time, the magneto is cut out by grounding the
primary circuit through terminals fe, k\ l\ and /. The magneto
armature continues to revolve, but no high-tension current is
generated because the primary current is short-circuited through
the ground and does not pass through the magneto interrupter.
The battery interrupter opens and closes the battery circuit,
so that a high-tension current is induced in the secondary wind-
ing of the coil D and flows by way of the switch terminal m'

Fig. 29

to the terminal m on the distributor, from which point it is sent
to the spark plugs in the proper order.

When the switch handle is moved to the magneto position,
the battery circuit is disconnected and the high-tension cir-
cuit of the spark coil is opened at the switch. The magneto
is brought into use by opening the grounded wire at terminal k'
on the switch and connecting the high-tension terminal n'
to the distributor terminal w'. A high-tension current 'is
generated in the magneto in the regular way, and it is delivered,
by way of the magneto terminal n, through the switch and to
the distributor.

Digitized by

Google

§8 ELECTRIC IGNITION 113

With the switch handle in the off-position, the low-tension
magneto circuit is grounded and the battery circuit is opened
at the switch; hence, neither the magneto nor battery can oper-
ate and no spark is formed. The different positions of the
switch handle are plainly marked on the face of the switch
by B, M, and Off, meaning, respectively, battery position,
magneto position, and off-position.

70. For the purpose of starting on the spark, the Bosch
coil is provided with a vibrator that is connected in parallel
with the battery interrupter in the coil circuit and that may be
brought into use by pressing a button x, Fig. 29 (6), located in
the center of the end plate of the coil. A pressure on this but-
ton will close the battery circuit through the vibrator and coil,
so that a high-tension current will be induced in the secondary
winding, provided the engine has not stopped with the battery
interrupter contacts closed. In such a case, the battery circuit
will already be complete and no spark will be formed. How-
ever, the connections of the push button are such that whbn
the battery interrupter is already closed it can be momentarily
opened by pressing upon the button and then quickly releasing
it; hence, a current of high voltage can be produced for all posi-
tions of the crank-shaft. The high-tension current thus gen-
erated will be sent to the spark plug in the cylinder whose
piston is on its working stroke; therefore, if there is a com-
bustible mixture in that cylinder, an explosion will result and
the engine will start. Obviously, the spark advance lever
must be in its fully retarded position.

71. Construction of tlie Elsemann Dual Magneto.

In the Eisemann dual ignition system, as in the Bosch system,
the magneto does not differ from the ordinary independent,
or single, magneto except in the addition of a battery inter-
rupter and a central distributor terminal. It is the usual type
of high-tension magneto, employing horseshoe magnets and
a* double-woimd armature. A front view of the magneto,
with the timing lever and end cap a removed so as to show
the interrupting mechanism, is illustrated in Fig. 30. The
battery interrupter consists essentially of the interrupter

Digitized by

Google

114 ELECTRIC IGNITION §8

lever 6, the contact screw c, and a two-lobed cam, not shown in
the illustration. The intenupter lever is pivoted on the inter-
rupter housing at d, and is rocked by means of a steel cam
fitted at the back of the regular magneto interrupter, this
cam rotating with the armature. The cam contains two pro-
jections, and as these pass the lower end of the interrupter
lever they press it out and thus separate the platinum con-
tacts at e. The interrupter lever b forms part of the battery
circuit; therefore, when the contacts are separated, the bat-
tery current is interrupted and a current of high voltage is

induced in the sec-
ondary winding of an
induction coil that is
also connected in this
circuit.

72. The regular
magneto interrupting
mecham'sm is shown
also in Fig. 30. The
entire mechanism ex-
cept the cams / and g,
which are located on
the timing lever, is
p,j, 3Q fitted to the armature

shaft and rotates with
it. The interrupter lever h is pivoted at ; on the bronze plate k,
so that, as the end / passes over the cams / and g, the platinum
contacts at m are separated. As these contacts form part of the
primary circuit of the magneto, the primary current is interrupted
when they are separated and a high-tension current is induced in
the secondary winding of the armature. The variation of the
time of ignition by both battery and magneto current is effected
by rotating the timing lever a by means of the arms n. As
the cams / and g are carried backwards or forwards, the sparfc
produced by the magneto occurs earUer or later in the revo-
lution of the armature. If the cams are carried backwards, or
in the opposite direction from that in which the armature is

Digitized by

Google

§8 ELECTRIC IGNITION 115

revolving, the spark will be advanced; and, if they are moved
forwards, or in the same direction in which the armature is
revolving, it will be retarded. Rotating the timing lever a
also rocks the battery interrupter; hence, when the current
is being ftimished by the battery, the time of interruption is
made earlier or later by moving the arms n backwards or
forwards, just as when the magneto current is employed.

As in the Bosch dual magneto system, the secondary current
does not flow directly from the annatiu"e to the distributor
through the nmgneto itself, but is carried to the switch on the
dash by a high-tension cable and from there to the central
terminal o, Fig. 30, on the distributor. The glass disk p in the
distributor plate is for the purpose of ascertaining through
which terminal the high-tension current is passing. Num-
bers from 1 to 4 are arranged on the movable part of the dis-
tributor, so that when number 1 appears at the glass the cur-
rent is being sent through terminal number 1, when number 2
appears it is being sent through terminal ntimber 2y and so on.

73. Wiring Diagram for the Elsemann Dual System.

The wiring diagram for the Eisemann dual ignition system is
indicated in Fig. 31, A being a front view of the magneto,
showing the low-tension connections of the interrupter and the
high-tension connections at the distributor, and A\ a side
view, showing the high-tension connection by means of which
the secondary current is led from the armature to the switch.
The transformer coil and switch is shown at B, the battery
at C, and the switch handle at e. The positions to which the
handle is moved for running on the magneto or on the bat-
tery, or for cutting out the ignition entirely are marked on the
switch end of the coil by the letters M, B, and O, respectively.

74. When the handle e is moved to the battery position,
the switch terminals/' and g' are so connected that the magneto
is grounded through / at g and is therefore inoperative. At
the same time, connections are made from the terminal ;'
on the switch, through the primary winding of the induction
coil and through the battery interrupter on the magneto, by
way of the terminals k' and k. The battery current flows

Digitized by

Google

116

Digitized by

Google

§ 8 ELECTRIC IGNITION 117

through these connections and back to the tenniiial m on the
battery by way of the magneto frame and the grotmd. Open-
ing the battery circtdt by the battery interrupter induces a
high-tension current in the secondary winding of the induc-
tion coil, and this current flows, by way of the terminal h' on
the switch, to the central terminal h on the distributor.

When the s^^dtch handle is in the magneto position, the bat-
tery circuit is opened, rendering the battery inoperative; also,
the connection between the switch terminals/' and g' is broken,
so that the primary current from the magneto flows from the
primary winding on the armature through the magneto inter-
rupter and back to the armatiu-e by way of the magneto body
and the armattire core. At the same time, the switch terminals
/' and k' are coimected, and the high-tension current induced
in the secondary winding of the armature is carried from the
terminal / on the magneto, through the switch, to the central
terminal h on the distributor. Placing the switch handle in
the off-position grotmds the primary circuit of the magneto
and also opens the battery circuit; hence, no current flows
from either source and the ignition is completely cut off.

The coil B used in this system is of the non-vibrator trans-
former type, but it is provided with a vibrator, or interrupter,
that can be operated by pressing the button x. This inter-
rupter forms a part of the battery circuit* and by means of
it, this circuit can be closed and opened by hand and the engine
started on the spark, provided a combustible mixture has been
drawn into the cylinder that is ready to be fired.

DOUBLE IGNmON SYSTEMS

DEFINITIONS

75. A double Ignition system, as the name implies, con-
sists of two entirely separate and distinct systems, either one
of which may be used wholly independent of the other. As in
the dual system, two sources of current are employed. These
may be either a magneto and a battery or a direct-current

Digitized by

Google

118 ELECTRIC IGNITION §8

dynamo and a battery. However, the double system differs
from the dual system in that two sets of spark plugs are
used. One set is connected in the magneto or dynamo cir-
cuit, and the other set in the battery circuit. The two cir-
cuits are brought together at a switch on the dash of the auto-
mobile, and they are connected in such a manner that ignition
may be obtained either by the generator with one set of spark
plugs or by the battery with the other set of spark plugs, or
it may be obtained by the generator and battery acting together
with both sets of spark plugs. The desired connections are
made by moving the switch handle to the correct position.
In some double systems, a regular high-tension magneto and
a dry-ceU battery or a storage battery are used for generating
the current; in other systems, a direct-current dynamo and a
battery are employed. In either case, the generator or the
battery may be used for ignition with the other circuit entirely
removed from the engine.

DOUBLE SYSTEM WITH MAGNETO AND BATTEBT

76. Boscii Double System. — In the Bosch double sys-
tem of ignition, a regular high-tension nmgneto, such as is
used for single ignition, supplies current for one set of spark
plugs and either a storage battery or a dry-cell battery sup-
plies current for the other set. The magneto and battery
circuits are brought together at the switch, which is incorporated
in the induction coil for the battery circuit and located on the
dash of the automobile. A single coil is used for all the cylin-
ders, and a combined timer and distributor is connected in
the battery circuit for interrupting the primary current and
distributing the secondary current to the spark plugs. The
magneto primary current is of course interrupted in the reg-
ular way by the magneto interrupter, and the secondary cur-
rent generated in the nmgneto is distributed by the magneto
distributor, as in a single ignition system.

77. An end view and a cross-section of the coil used
with the Bosch double system are shown in Fig. 32. As illus-
trated, the coil is in position on the dash a so that the switch

Digitized by

Google

§ 8 ELECTRIC IGNITION 119

can be operated from the driver's seat. The switch is manip-
tdated by the handle 6, which turns the coil cover c and thus
moves the coil d through a pin connection, not shown in the
illustration. The movable switch plate e carries the terminals
from the coil; therefore, the contacts can be made to register

Pig. 32

with similar contacts on the stationary plate /. The desired
connections are made by rotating the coil d by means of the
cover c, and thus causing the different switch contacts on the
plates e and / to engage. The coil proper consists of a cylin-
drical iron core, on which are wound the primary and secondary

Digitized by

Google

120 ELECTRIC IGNITION § 8

windings. The primary winding is connected at one end to
a contact segment on the plate e, and at the other end to the
vibrator blade g, through which it is grotmded. The sec-
ondary wire is connected at one end to the contact segment,
through which the current flows to the distributor, and at the
other end to the ground connection. The purpose of the but-
ton A is to start the engine on the spark. When the switch
handle is either in the battery position or in the magneto-bat-
tery position, a pressure on this button induces a high-tension

Pig. 33

current which is sent to the distributor through the terminal /.
The switch positions are marked on the face of the coil as fol-
lows: The off-position is marked 0; the battery position, B\
the position for operating both battery and nmgneto at the same
time, A© ; and the magneto position, M, The switch is provided
with a locking key k, by mesms of which it may be locked in the
off-position so as to prevent luiauthorized use of the engine.

Digitized by

Google

§ 8 ELECTRIC IGNITION 121

78. The combined tuner and distributor used in this
system is illustrated in Fig. 33, (a) being an external view;
(6), a cross-section; and (c), a longitudinal section. The timer
proper is operated at the same speed as the cam-shaft by the
sleeve shaft a, which carries the steel cam b. The cam has
four lobes, or projections, that raise the lever c four times per
revolution, or once for each working stroke of a four-cylinder,
four-cycle engine, thus breaking the primary circuit and pro-
ducing a spark at the required time. The timer is connected
to the battery wire at the binding post d and is grounded at e,
•so that the lever c forms part of the battery circuit when the
switch handle of the coil is in the battery position. The dis-
tributor part of the device is also driven at cam-shaft speed,
being attached to the shaft a by the screw / and the plate g.
The distributor consists essentially of the disk h, which con-
tains four terminals ; arranged regularly around the disk, and
the rotating plate ^, which carries a carbon brush /. A second
carbon brush m extends from the central distributor terminal n
to the movable brush /, which is enclosed in a rectangular brass
tube. When in operation, the high-tension current is carried
to the brush / through the brush m, and from I it is sent suc-
cessively to the terminals /. As the plate k rotates, the brush I
is brought into contact with the terminals at the same instant
that the primary circuit is broken by the timer; therefore,
the current is transmitted to the spark plugs in the proper
order.

79. Wiring Diagram for the Bosch Double System.

The wiring diagram for the Bosch double ignition system is
illustrated in Fig. 34. In view (a), the magneto is shown
at A, the battery at B, the coil at C, and the timer-distributor
at D. View (6) is a side view showing the coil in position on
the dash. The wiring connections are such that, when the
switch is in the off-position, the battery circuit through the
terminal a is broken and the magneto circuit is grounded
through the terminal b. Both circuits are thus made inoper-
ative, so that no spark is formed and all ignition is cut off.
When the switch is placed in the battery position, the magneto

222B-n32

Digitized by

Google

122 ELECTRIC IGNITION § 8

remains grounded, but the battery circuit is closed through the
terminals a and c\ therefore, a complete circuit is formed
through the dash coil, the timer-distributor, and the ground.
It is thus evident that a current will be produced in the sec-
ondary winding of the coil when the battery circuit is broken
by the timer. This high-tension current flows by way of the
terminal d to the distributor, from which it is transmitted to the
battery spark plugs e. With the switch in the battery-magneto
position, the battery circuit operates as just described and the
magneto ground circuit is broken, hence the magneto also

Fig. 34

product a high-tension current. The current from the mag-
neto is generated and transmitted to the magneto spark plugs/
in exactly the same manner as the current in the independent,
or single, ignition magneto. Under these conditions, a spark
is produced in both sets of spark plugs at the same instant.
With the switch in the magneto position, the magneto operates,
but the battery circuit is broken so that sparks occur only in
the spark plugs /.

80. In an automobile equipped with the Bosch double
ignition system, the engine is started on the spark by pressing

Digitized by

Google

§ 8 ELECTRIC IGNITION 123

the button x with the switch in the battery or the magneto-
battery position, provided, of course, that the rotor of the dis-
tributor is in contact with the distributor segment connected
to the spark plug in the cylinder that is at that iostant on its
power stroke. A pressure on this button completes the bat-
tery circuit through the vibrator blade g, Fig. 32, and thus
produces the required spark.

DOUBLE SYSTEM WITH DYNAMO AND BATTERY

81. Since the advent of the electric self-starter, which
requires the services of a dynamo and a storage battery, there
has come into use a double ignition system that employs a
direct-current generator and a storage battery in one circuit
and a set of dry cells in the other. In this system, the two cir-
cuits are entirely independent of each other, being brought
together at a switch, by means of which either one may be put
into operation.

For ordinary running, the ignition current is obtained either
from the dynamo or the storage battery, which is connected
by the method known as "floating the battery on the Une."
At low speeds, say when the engine is running at less than
300 revolutions per minute, the current comes from the
storage battery; at higher speeds, it comes from the dynamo.
Besides supplying most of the current for ignition, the dynamo
automatically charges the storage battery in the manner
employed with the "battery floated on the line." The dynamo,
of course, generates a low-tension current, so that an induction
coU is required to produce a current with a voltage high enough
to create a spark in the spark plug. The dry-battery circuit
is used as an auxiliary, and it is switched on only when, in case
of accident, or for some other reason, the dynamo circuit can-
not be operated. The dry-battery circuit usually contains
an independent coil and distributor; therefore, it can be com-
pletely removed without affecting the other circuit.

82. In the type of double system under discussion, the
storage battery is commonly used to supply current for elec-
tric lighting and for operating an electric self-starter. For

Digitized by

Google

124 ELECTRIC IGNITION § 8

starting without hand-cranking, the djmamo is temporarily
and automatically transformed into a motor, which, when
set in operation by current from the storage battery, rotates
the engine until it commences to move under its own power.

MISCELLANEOUS IGNITION SYSTEMS

TWO-POINT MAONETO STSTEIC

83. In the two-point, or two-spark, magneto ignition
system, there is employed a high-tension magneto that will
deliver a spark to two spark pltigs at the same instant. In
order to make tise of this system, an automobile engine must
be provided with two separate sets of spark pltigs; that is,
two spark plugs in each cylinder. Two sparks can then be
made to occur in each cylinder at the same instant, and the
combustible mixture will be ignited at two points instead of
one, as in the single-spark system; also, the length of time
required for total infiammation of the charge will not be so
great. In order to secure the best results, the spark plugs
should not be located close together, but should be separated
by a distance of at least one-half of the entire width of the
combustion chamber. The object of thus locating the spark
plugs is to place them in the center of practically equal voliunes
of gas, so that the spread of flame throughout the whole charge
will be as rapid as possible. Decreasing the length of time
required to btim the charge also decreases the spark advance
necessary and hence saves power, because, when the spark is
advanced, ignition occurs before the end of the compression
stroke, so that the charge has begun to bum and expand while
it is still being compressed. Thus, the advantage claimed for
the two-point ignition over the single-point system is that the
power developed by the engine is increased on accoimt of the
more rapid inflammation of the charge and consequent less
advance of the spark.

84. Construction of Magneto. — ^The magneto used in
the two-point system of ignition is constructed along the same

Digitized by

Google

§ 8 ELECTRIC IGNITION 125

lines as the ordinary single-spaxk, high-tension magneto,
the only difference being that there is used a double distributor,
which, of course, requires special electrical connections to the
armature. The distributor is of double thickness, so that
two sets of distributor terminals can be accommodated side
by side. For a four-cylinder engine, there are eight distributor
terminals; for a six-cylinder engine, twelve terminals; etc.
In one make of magneto, the desired result is obtained by con-
necting the two ends of the secondary winding to two segments
located opposite each other on the collector ring. Two col-

Fig. 36

lector brushes are provided, one being connected to the inner
half of the distributor by a conducting bridge similar to that
used on single-spark magnetos, and the other to the outer half
by a cable passing aroimd the magnets. These brushes col-
lect the high-tension current at the same instant and deUver
it to the distributor. The distributor is provided with two
rotating arms, or brushes, insulated from each other, that
deliver the current to the two sets of terminals. Two safety
spark gaps are used in this magneto.

85. Wiring Diagram for the Boscli Two-Point
Ignition. — The wiring diagram for the Bosch two-point

Digitized by

Google

126 ELECTRIC IGNITION §8

ignition system as applied to a four-cylinder engine is illtis-
trated in Fig. 35. In view (a), the high-tension magneto,
with a portion of the magnets removed so as to expose the con-
nections, is shown at A, and the switch at B, In this view
is shown the back of the switch B with the magneto and
ground connections, while in view (6) is shown the face of the
switch. The double distributor, with the high-tension cables
running to the two sets of spark plugs, is located at d and e
on the magneto, and the two collector brushes that take high-
tension cturent from the armature collector ring are located
at / and g. The safety spark gaps are shown at h and ;, one
being connected in each secondary circuit for the protection
of the armature winding. The collector brush / is connected
by way of the safety spark gap h to the distributor half d by
the cable k, and the collector brush g is connected to the dis-
tributor half e by way of the safety gap ; by the connections I
and m.

The switch connections are rather simple. The switch ter-
minal 0 is connected to the magneto interrupter n by the pri-
mary cable p, and the switch terminal x is connected to the
collector brush g by the high-tension cable q\ the switch ter-
minal y is groimded. When the switch handle r is placed
in the position indicated in view (6), the collector brush g is
grotmded through the terminal y, view (a), and no current
flows to the half e of the distributor. Under these conditions,
high-tension current flows through only the cable k to d and is
transmitted to but one set of spark plugs. With the switch
handle placed in the position marked O, the magneto inter-
rupter n is grounded and no high-tension current is produced;
this, therefore, is the off-position. With *the handle placed
in the position marked Af , no connections are made through
the switch, and current is transmitted to both halves of the
distributor over the cables k and /, so that sparks occur in both
sets of spark plugs. Thus, by placing the switch handle in
any one of these three positions, the ignition may be cut out
entirely, one set of spark plugs may be operated, or both sets
may be operated.

Digitized by

Google

§ 8 ELECTRIC IGNITION 127

DUPLEX lONinON SYSTEM

86* In the so-called duplex system of ignition, the

current is supplied by a high-tension magneto and a battery
so connected that both make use of the same circuit at the same
time. The primary and secondary windings of the magneto
armature are employed to change the battery current to a
current of high electromotive force. Therefore, no separate
induction coil is used, but a kick coil with a single winding is
connected in the battery circuit for the purpose of strengthening
the primary current.

87. The magneto used in the duplex system of ignition
is of the ordinary shuttle-wotmd, high-tension type, being pro-
vided with two bind-
ing posts on the cover
of the interrupter in-
stead of one, as in
other systems. A
front view of the
Bosch duplex mag-
neto, which is de-
signed for use in this
sjTstem, is shown in
Fig. 36, the timing
control lever a and
the interrupter cover b
being removed in
order to expose the

interrupter medla-
rs. . . Pig. 36

msm. The timing

control lever a contains the cams c, upon which the interrupter
lever d strikes to separate the contact points e and /; also, the
interrupter cover b is fitted with two contact segments g
and A, which are connected to the two binding posts on
the cover, and which make contact with the carbon brushes k
and /. One of the binding posts is shown at ;, but the
other is hidden by the cover b. One brush k is electrically

Digitized by

Google

128 ELECTRIC IGNITION § 8

cx)nnected to the interrupter lever d, while the other brush /
is connected to the insulated side of the interrupter, which
leads to the primary winding of the magneto armattire. When
in operation, the positive terminal of the battery is con-
nected to the binding post leading to the contact segment g,
and the negative terminal to the binding post leading to seg-
ment h\ thus, when the armature of the magneto is stationary
and the interrupter points aiie closed, the current will flow from
the positive terminal of the battery to the contact segment g
and the brush /, and thence through the interrupter and back
to the negative terminal of the battery by way of the brush k
and the segment k. When the interrupter points are sep-
arated, current will flow from the contact brush / through the
primary winding of the armature and back to the battery
through the brush k; therefore, by quickly breaking the cir-
cuit at the interrupter, there will be induced in the secondary
winding a high-tension current that will have sufficient elec-
tromotive force to cause a spark to occur in a spark plug,
provided the rotor of the distributor makes contact with a
distributor segment connected at that instant to the plug.
An engine employing this system can be started on the spark
by pressing a push button, provided the engine has come to
rest in such a position that the interrupter is open. The bat-
tery circuit is thus broken and the required high-tension cur-
rent is produced in the secondary coil of the magneto armatiu^.
When the magneto and the battery are both in operation,
the contact brushes I and k rotate with the armature; there-
fore, the battery current changes direction through the primary
winding twice during each revolution. At the same time, an
alternating current is generated in the primary winding of the
magneto armature, and it also changes direction twice during
each revolution; however, it always flows in a direction opposite
that in which the battery current flows. On account of this,
the battery current opposes the magneto current; hence, when
the magneto is running at a low rate of speed, the high-tension
current induced in the secondary winding of the armature
is due to the interruption of the battery current, which, at that
instant, is stronger than the magneto current and therefore

Digitized by

Google

§ 8 ELECTRIC IGNITION 129

predominates in the primary winding. When the magneto is
running at a high rate of speed, the magneto current pre-
dominates; and, when the interrupter points are separated,
this current is stopped and the battery current is sent through
the primary winding in a direction opposite that in which the
magneto current had been flowing. This has the same effect
as a reversal of current, so that a current with a voltage high
enough to produce a spark is induced in the secondary winding.
When the battery is cut out of the circuit entirely, the high-
tension current is generated in the regular way by the magneto.

(a)
Pic. 37

In this system, the primary purpose of the battery is to supply
current to the armattire winding in order to supplement the
magneto current when starting the engine by hand-cranking
and to supply ciurent for starting on the spark.

88. The wiring diagram for the Bosch duplex system is
illustrated in Fig. 37. In view (a) the high-tension magneto
is shown at A, the battery at B, and the combined switch and
kick coil at C; also, the spark plugs are shown at D. View
(a) shows the coil in its horizontal position on the dash fe, and
view (t) is a view of the face of the switch. * The radiator
of the engine is shown at g and the dash at A, in order to

Digitized by

Google

130 ELECTRIC IGNITION § 8

give an idea of the relative location of the different parts of
the system.

When the switch handle / is moved to the off-position, the
battery circuit is broken and the two wires leading to the mag-
neto are connected together at the switch, thus short-circuit-
ing the magneto current. This cuts out all ignition, for which
reason no spark is formed. When the handle is placed in the
magneto position, the battery circuit remains broken at the
switch, but the wires leading from the magneto are separated
so that the primary current generated in the armature flows
through the interrupter and generates a high-tension current,
which, in turn, produces the necessary spark. In this case,
the spark is produced by the magneto alone. With the handle
in the battery position, the battery is connected to the mag-
neto, and the spark is generated by the interruption of both
the magneto current and the battery current, as previously
explained.

Digitized by

Google

TRANSMISSION AND CONTROL
MECHANISM

(PART 1)

FRICTION CLUTCHES

CONSTRUCTION AND OPERATION

PURPOSE OF CLUTCHES

1. In an automobile driven by an intemal-combnstion
engine, means mxist be provided for connecting the engine to
the transmission gearing or disconnecting it from this gearing,
either while the gears are being shifted or when the car is to
be stopped with the engine running. This is necessary in the
first case because, with the ordinary form of transmission, or
speed-changing, gears, the engine must be disconnected from
the gearing while the speed is being changed in order to make
a smooth and noiseless shift and to avoid injury to the mecha-
nism. In the second case, it is necessary when it is desired to
stop the car for a short time without stopping the engine or when
the car must be stopped suddenly, as in an emergency. For
the purpose named, a friction clutcli of some suitable form
is employed in nearly all cars. The clutch forms part of the
engine in most cars, but in others it is incorporated in the
same housing with the gears by which the speed of travel of
the car is regulated. Cars containing a so-called friction

COPYRIOHTED BY INTERNATfONAL TEXTBOOK COMPANY. ALL RIOHTS RKBVRVED

Digitized by

Google

2 TRANSMISSION AND CONTROL . § 9

transmission do not need a clutch, as its function is performed
by separating the diflferent members of such a transmission.

2. Some of the most important qualifications that the
friction clutch must fulfil in order tp give satisfactory operation
in automobile service are as follows:

1. It should engage without seizing and jerking the car.

2. It should hold without slipping after the car has been
started and the clutch is in full engagement, except imder
very unusual conditions in which the speed of rotation of the
road wheels is very suddenly checked.

3. It should release instantly, without dragging the driven
parts arotmd, as soon as the disengaging mechanism is
operated.

4. It should be of such form that the driven side will have
a minimum tendency to keep rotating by its own momen-
tum after the clutch is released. In other words, the fljrwhed
action of the part of the clutch that is connected to the power-
transmitting mechanism should be a minimum.

5. It should not require constant adjustment and atten-
tion to keep it operating properly.

6. All parts should be of proper strength and possess lasting
qualities.

3. The friction clutches used in automobiles are of several
general types, depending on the manner in which the required
friction is produced. These types, or classes, are the cone
dutch, disk clutch, expanding clutch, and contracting clutch. In
each case, however, an adequate device must be employed for
bringing the members of the clutch in contact.

In the cone clutcli, the necessary friction is produced by
forcing two cone-shaped members together, one within the
other, so that the conical surfaces come in contact. One
member of the clutch is driven by the engine while the
other member is attached to the propeller shaft or transmis-
sion shaft.

The disk clutcli makes use of a number of plates, or disks,
that are forced together. One set of disks is attached to the
engine shaft and the other set to the propeller shaft or trans-

Digitized by

Google

§9 MECHANISM 3

mission shaft. The large number of disks forms a sufficiently
large cx)ntact surface to produce the required friction when the
plates are pressed together.

In the expanding clutch, two cylindrical members are
used, one within the other. The diameter of the inner member
can be increased, thus forcing it outwards against the outer
part and causing the desired friction.

The contracting clutcli diflE ers from the expanding clutch
only in that the outer member is of variable diameter, which
may be decreased. The outer member can thus be tightened
about the inner one and the required friction produced.

CONE CLUTCHES

4. Ordinary Form of Cone Clutdi* — ^A cone clutch
of the form used on a large number of automobiles is shown in
Fig. 1. In view (a), the members are shown separately while
in (t) they are shown in engagement. The internal cone a
is free to slide on the ends of the transmission shaft and crank-
shaft, both of which extend into it, but it is prevented from
rotating on the transmission shaft by the use of feather keys b.
The external cone c is formed in the flywheel of the engine and
rotates with the crank-shaft, to which it is rigidly attached.
When these two members are brought together with the stu*-
face d of the internal cone in contact with the surface e of the
external cone, as in (6), they are said to be in engagement. If
the external cone c is rotating and the internal cone a is engaged
with it, the friction of these surfaces against each other will
cause the external cone to transmit a turning effort, or torque,
to the internal cone, and thus carry this cone around with it.
The extent of this tendency to drive the internal cone is pro-
portional, at least in a measure, to the pressiu-e between the
conical friction surfaces at d and e. On account of the conical
shape of the friction surfaces, there is a wedge-Uke action
that gives a pressure between them that is much greater than
the force that pressed the driven cone toward and against
the driver. For a given force acting to press the inner cone
toward the outer one, the more nearly the conical surfaces

Digitized by

Google

4 TRANSMISSION AND CONTROL § 9

approach a cylindrical form, the greater will be the pressure
between them.

5. The cone clutch shown in Fig. 1 is employed in model 15
of the Northway power plant. The internal cone a is of

;«;

Pic. 1

aluminum and is faced with leather while the external cone,
or flywheel, c is of cast iron. The leather-faced cone is used
on accoimt of the greater frictional resistance to sUding between
leather and metal than between metal and metal. When the
clutch is engaged, as in (t), the members are held in contact

Digitized by

Google

§9 MECHANISM 5

by the spring /, which is ia compression between the internal
cone a and a spring seat, or stop, g. The seat g is prevented
from sliding in the direction of the axis of the shaft by three
bolts h that extend through the web of the internal cone and are
secured at their inner ends to a sleeve on the end of the crank-
shaft. The sleeve prevents the bolts from moving endwise
and thus holds the seat g always at the same distance from the
external cone c. The spring is
compressed and the clutch re-
leased by moving to the left
the sleeve i, which is attached
to the internal cone a, and hence
withdraws this cone from the
external cone c.

By the use of this device, the
car can be started 'gently by
allowing the inner cone to be-
come engaged slowly with the
outer one and permitting the lat-
ter to slip around over the
driven cone, but at the same
time gradually starting it to
rotate and iacreasing its speed
of rotation. The rotation of
the driven cone is of course re-
sisted by the force required to
start and move the car. The
strength of the clutch spring
should be suflSdent to force the
cones together hard enough to

prevent slipping under ordinary conditions after the pressure
employed in holding the cones apart has been removed.

6. In the cone clutch, the closing spring is often enclosed
instead of being in plain view as in the clutch shown in Fig. 1.
An example of a clutch having the spring enclosed is that used
on the Studebaker, model 35, car. This clutch is shown in
section in Fig. 2. The external cone is formed in the flywheel a,

Digitized by

Google

6 TRANSMISSION AND CONTROL § 9

which is bolted to a flange b on the crank-shaft by means of
the bolts c. The internal cone d is of stamped steel and is
faced with leather, as shown at e. Under the leather face of the
cone is a series of flat springs/ that allow the leather surface to
engage gently with the inside of the fljrwheel. These springs
are arranged in a shallow groove on the outside of the cone and
are of such form that they slightly lift the leather when the
clutch is disengaged, so that certain portions of the leather
come in contact with the flywheel rim first. Unless some
external force is applied to prevent it, the clutch is held in
engagement by the heavy coil spring g that is compressed
between the hub k of the inner cone and a thrust bearing i car-
ried on the end of the
crank-shaft. The clutch is
disengaged by forcing the
hub k to the left by means
of a yoke that surrounds
the groove / and is con-
nected by suitable levers to
a pedsl. When the pedal
^ is pressed forwards, the
spring is compressed and
the inner cone moved back
from the flywheel. The
part k is connected to the
^^^ propeller shaft by a tmi-

versal joint that has a sliding connection, which allows the inner
cone a to be drawn back without changing the position of the
propeller shaft. Part of the imiversal joint is shown at k.
When the clutch is disengaged, the hub k ttuns on a bushing /
and on the thrust bearing i. The clutch spring may be
tightened or loosened by turning the nut m.

7. Multiple-Spring Clutcli. — Instead of being provided
with a single dutch-closing spring, some clutches have several
comparatively small springs arranged at equal angular dis-
tances around the clutch shaft. An external view of the
Cadillac cone clutch, which is of this type, is shown in Fig. 3

Digitized by

Google

59 MECHANISM 7

and a sectional view is shown in Fig. 4. Like parts in the two
views are lettered the same as far as possible; hence, both illus-
trations should be referred to in connection with the following
description.

In this clutch, the external cone is a malleable-iron cast ring a
that is bolted to the flywheel by means of stud bolts b. The
inner cone c is of pressed steel and is leather faced. It is held
in engagement by six springs d; the spring bolts e extend
through the web of the inner cone and are secured to a flange /
that is not free to slide on the engine shaft, so that when no
external force is applied, the two members are drawn together.
The clutch is disengaged by forcing the inner cone rearwards
against the resistance of the springs.

A feature of this clutch is the construction of the ring a that
forms the outer cone. The conical part of this ring to the rear
of the flange is spUt at eight points, thus dividing it into eight
sections. At the end of each section the ring is slotted, as at g,
and a part h is sprung inwards. This part forms a spring that
causes the clutch to take hold gradually when the inner cone is
pressed inwards. The clutch springs are adjusted by varying
the tension on them by means of the nuts i,

8. The operating mechanism of the clutch is shown in
Fig. 4. A pressure forwards on the clutch pedal forces the
thrust bearing / and the sleeve k toward the rear of the car.
This movement of the sleeve k withdraws the inner cone c
from the outer cone a, thus compressing the springs d and
releasing the clutch. Normally, when no pressure is exerted
on the pedal, the springs d hold the cones in engagement.
The shaft / is an extension of the engine crank-shaft, but the
bearing m that carries the flange / rotates with the inner cone c.
The bearing w, and hence the flange /, is prevented from
moving endwise by the thrust bearing n. The coupling o allows
the sleeve k to sUde without sHding the transmission shaft.

Connected with this clutch is a clutcli braJ^e, which is
used for decreasing the speed of the driven member of the
clutch when the cones are separated and the transmission gears
are disengaged, as when changing speed from a low to a higher

Digitized by

Google

Digitized by VjOOQ IC

§9 MECHANISM 9

gear. The brake consists of the metal disk p, which revolves
with the transmission shaft, and a brake shoe q faced with some
antifriction material r. For the sake of clearness, the brake
shoe is here shown at some distance from the disk p, but in
actual practice it is located close to the disk; hence, when the
clutch is disengaged, a further movement of the pedal draws the
antifriction material against the disk by means of a rod 5,
and thus decreases the speed of the free member of the clutch.

The rod t is a stayrod by means of which the point where the
clutch pedal in its downward course begins to throw out the
clutch may be adjusted. This adjustment is made by screw-
ing up the nuts m, thus shortening the distance between the
bracket v and the yoke w, or by unscrewing these nuts with
the opposite effect. Screwing the nuts right-handed swings the
yoke w on its contact fingers, which are located on each side of
the center of the yoke, and rotates the clutch pedal in a clock-
wise direction, raising it higher above the floor boards. This
adjustment causes the action of the i)edal to take effect at an
early point in its downward movement. The pedal may be made
to act at a later point by turning the nuts in a left-hand direction.

The outer circumference of the flywheel is provided with
teeth X with which a gear of the electric self-starting device
engages when the engine is being cranked by means of the
starter.

9. Reversed Ck)ne Clutclies. — In the cone clutches thus
far described, the cones are so arranged that engagement is
made when the inner cone is pressed forwards, or toward the
flywheel, and the external cone is usually the rim of the
flywheel. In the reversed cone clutch, engagement is made
when the inner cone is forced in the opposite direction, or to the
rear, and the external cone must be a separate piece bolted to
the flywheel.

An example of a reversed cone clutch is shown in Fig. 5,
which is a sectional view of the clutch used on the Studebaker
**20*' automobile. The internal cone a is of aluminum and is
leather faced, the leather being held in place by rivets b. The
external cone c is a separate casting bolted to the fljrwheel d by

Digitized by

Google

Digitized by VjOOQ IC

§ 9 MECHANISM 11

bolts e. The fl3rwheel in turn is keyed to the engine crank-
shaft / and hence rotates with it. Motion is transmitted from
the inner cone a to the propeller shaft g through the hub K a slid-
ing joint iy and a universal joint /. Whsn no external force is
applied to prevent it, the clutch is held in the engaged position
by the closing spring k, which is compressed between the inner
part of the hub k and the cone sleeve /. A ball thrust bearing m
between the end of the sleeve / and the web of the flywheel
takes the thrust of the spring. The clutch is disengaged by
forcing the hub h toward the flywheel, thus compressing the
spring k and slipping the inner cone into the larger interior of
the flywheel. As the clutch is released, the hub of the inner
cone slides on the sleeve I and on
the clutch shaft n. A sliding
connection with the proi)eller
shaft that permits this move-
ment of the clutch is made by
means of the sliding universal
joint t, A gentle engagement of
the members of the clutch is ob-
tained by means of a rubber in-
sert o that fits around the cone a
under the leather face.

10* Methods of Securing
ClutchL Facing. — ^Where
leather is employed as a clutch ^°' ®

facing, it is usually secured to the inner cone by means of cop-
per belt rivets, the heads of which are countersimk in the siu-f ace
of the leather. This means of fastening the clutch leather is
illustrated at 6, Fig. 5. An exception to this method is that
used in the White cone clutch, the inner cone of which is shown
in Fig. 6. In this clutch, the leather facing a is held in place
by T bolts b that fit in grooves in the rim of the clutch. The
grooves are deep enough to prevent the bolts from coming into
contact with the inner surface of the flywheel. The T bolts
extend through the clutch rim and are secured by nuts; these
nuts in the illustration are hidden by the spokes of the clutch

Digitized by

Google

TRANSMISSION AND CONTROL

§9

casting. This method is especially applicable to clutches that
make use of material that does not rivet well, as, for example,
asbestos fabric.

Sometimes a small radial flange is provided on the edge of
the rim of the cone, as shown at p. Fig. 5, in order to help retain
the facing and take some of the stress oflE of the rivets.

11* Devices for Securing Smooth Clutx^li Engage-
ment.— In order to secure means of bringing a cone clutch into
engagement gently, various methods of causing a part of the
friction surface to come first into contact with the outer cone, and

then later all the fric-
tion facing into en-
gagement, have been
put into use. A com-
mon device for elimi-
nating more or less
the tendency of the
clutch to seize and
jerk, is shown in
Fig. 7 (a). In this
view, the external
cone is shown at a,
a part of the metal of
the internal cone at 6,
and the leather facing
at c, A plimger d is
set into the metal of the cone and is forced 6ut by an expansion
spring e against the inner side of the leather, its outward
motion being limited by a cotter pin in the stem of the pltmger.
This presses out the portion of the leather that is over the end
of the plimger, so that it stands higher than the other parts of
the leather facing. Several of these plungers are used in the
complete cone. When such a clutch is brought into engage-
ment, the high portions of the leather facing first come into
contact with the external cone; thus, the pressure against the
leather is limited to the expansive force of the springs e. The
clutch, therefore, does not grip suddenly and jerk.

<^)

Pio.7

Digitized by

Google

§ 9 MECHANISM 13

In view (6) is shown the side view of the flat spring/, Fig. 2,
which is largely used for securing a gentle engagement between
the clutch members. The spring a, Fig. 7 (fc), is usually secured
to the cone by a single rivet b and is slightly bent as shown.
As the clutch is engaged, the spring becomes flattened, thus
allowing the members to come together gradually. The clutch
leather is shown at c, and the pressed steel cone at d.

12, A gentle engagement of the members of a cone clutch
is sometimes secured by cutting holes through the friction facing
and inserting pieces of cork whose outer ends project slightly
above the face of the leather. The cork, if of good quality,
is easily compressed, so that it

has about the same action as

the facing forced out by the i

plimger. The tendency to cling \

is somewhat higher for the cork ^

than for leather in the condition
that ordinarily exists in service.
Clutches fitted as just described
are known as cork^nsert clutches.
An example of a cone clutch
fitted with cork inserts is that
used on the Pope-Hartford car,
the internal cone of which is
shown in Fig. 8. Tapered pock- ^^- ®

ets a, having a larger diameter at the bottom than at the top,
are cored into the rim of the cone. The pieces of cork b are
forced into these pockets tmder pressure and extend out through
the holes in the leather c sl distance of about t^ inch. The
clutch leather in this case is secured to the rim by the rivets d,

13. The angle between the cone surfaces and the shaft,
or axis, of the cones, is generally made as small as is possible
without getting the cone surfaces so nearly cylindrical as to
cause them to stick together imdtdy and thus prevent ready
release of the clutch. The angle is generally about 11°.

Digitized by

Google

14 TRANSMISSION AND CONTROL § 9

DISK CXUTCHES

14. Principle of Disk Clutcli. — In Fig. 9 is shown a
simple form of disk clutcli, which illustrates the principle on
which clutches of this type operate. It consists of a driving
shaft a and a driven shaft b, to which power is transmitted by the
friction disks c and d when their flat adjacent surfaces are
pressed together. If the friction surfaces are made entirely
flat so as to cover the complete areas within the circles that
form the outlines of the disks, the tendency is for the wear, due
to slipping, to be more rapid toward the periphery than at and
near the center of the disk. In order to obviate this imdesirable

feature, which reduces the
amount of turning effort that
can be transmitted from one disk
to the other, the disks are hol-
lowed out so that a ring is
formed at the periphery of each
I disk. Although, when modified
i in this manner, the bearing sur-
faces are no longer in the form
of disks, the name disk clutch is
universally applied to clutches
of this type. As the bearing
siirf aces are flat and are at right
angles to the direction of the
force that is applied to close
them, the pressure between the
friction surfaces, instead of being greater than the closing force,
as in cone clutches, is equal only to the amount of the closing
force. Therefore, for a given mean diameter, an equal extent
of friction surfaces, and the same closing force, a single pair of
frictional surfaces will not transmit as much turning effort in
the disk type of clutch as in the cone type.

16. In order to keep down the size of the disk clutch, as
well as the closing force, a number of friction disks, or rings, are
used in automobile practice. The multiplication of the friction

Digitized by

Google

§9 MECHANISM 15

surfaces in this manner increases the tiiming effort that the
clutch will transmit in the same proportion as the number
of pairs of frictional surfaces is increased. Thus, with two
pair of frictional surfaces, the turning effort will be twice
as great as with one pair, as shown in Fig. 9; provided, of
course, the friction stirfaces are of the same mean diameter
and extent, have the same coefficient of friction, and are
pressed together with the same pressure in each case. Thus,
if there are thirty pair of friction surfaces, the clutch will trans-
mit thirty times the turning effort that it would transmit with
only one pair.

16. An idea of the extent of increase of frictional effect
that is secured by increasing the number of pair of friction
surfaces can be obtained by the following simple experiment:
As shown diagrammatically in Pig. 10, lay together a nimiber
of sheets, or slips, of writing paper on a board or a box so that
the ends of alternate
sheets will overlap
each other half way ^
or more, and place a
weight, as a, of §
pound or moreon top p,q jq

of the overlapping

parts. The sheets are shown separated merely to make the
illustration dear; they really touch each other. Grasp the free
projecting ends b and c of the paper and pull the sheets apart
in opposite directions, as indicated by the arrowheads, so that
the overlapping sheets slip from between each other. Care
should be taken not to lift or ptdl upwards so as to raise the
paper and weight. First use two or three sheets; then increase
the number of sheets to thirty or more. The amount of pull
necessary to draw apart thirty sheets will be rather surprising
at first. This pull, as was stated in Art. 16, is proportional
to the number of pair of surfaces that slide, or rub, over each
other when the sheets are pulled apart. Clutches that are
made up of a number of disks, or plates, are usually known as
multiple-disk clutclies*

Digitized by

Google

16 TRANSMISSION AND CONTROL § 9

Multiple-disk clutches may be divided into two general
types, or classes, namely, dry-plate clutclies, or those in
which the disks require no lubrication, and oiled clutcliest or
those in which the disks are enclosed in an oil-tight case and
run in a bath of oil.

17. Dry-Plate Clutclies. — In the dry-plate clutch, lubri-
cation is made tmnecessary either by facing one set of disks
with asbestos fabric on both sides or by making use of cork
inserts. Both of these materials have good frictional qualities
when used on steel. The asbestos fabric is usually composed
of asbestos fiber and woven wire and is riveted to the plates.
The asbestos is used on account of its good frictional qualities
and its resistance to heat, while the wire is used to give the
asbestos the necessary strength. The cork inserts in disk
clutches serve the same purpose as in cone clutches; that is,
they provide a means for obtaining a smooth and gradual
engagement. When the clutch is engaged, the contact in cork-
insert clutches is^part cork on metal and part metal on metal,
the proportion of each depending on the size and number of
the corks.

The chief advantage of the dry-plate clutch is that it elimi-
nates the dragging due to improper lubrication, by dragging
being meant that the clutch fails to release properly when the
clutch-operating pedal is pushed forwards.

18. A typical dry-plate clutch employing disks faced with
asbestos fabric is that used in the Stevens-Duryea car. One
model of this clutch is shown partly in perspective and partly in
section in Fig. 1 1 . The plates a and b and the driving member c
are shown cut in half with the front halves removed in order to
expose to view the inner parts of the clutch. The disks consist
of six driving plates a, which are faced on both sides with quarter
sections of woven wire and asbestos, and seven driven plates b.
These disks are in reality rings and are provided with projections
that engage with grooves in the driving and driven members of
the clutch. The driving member c is a hollow cylinder provided
with six grooves d that engage with the projections e on the

Digitized by

Google

§ 9 MECHANISM 17

driving disks a in such a manner that the disks are free to slide
in the grooves but must rotate with the hollow cylinder.

The inner member / is also provided with six grooves g;
these grooves engage with projections on the inner edge of the
driven disks fc, which are free to slide in the grooves but must
rotate with the driven member /. This member is integral
with the driven shaft h. Inside of the inner member / and
surrounding the shaft h is the spider i, of which the ring /
is an integral part. The dutch-closing spring k is contained
within the spider i and is compressed between a shoulder in
the outer end of the spider sleeve and a web / of the inner
member /. The friction disks
are confined beftween the ring /
and a large nut m that is
screwed on the inner member g
and serves as a means of adjust-
ing the pressure on the disks.
The clutch is operated from a
pedal through the yoke n.

19. When in operation on
the car, the driving member c,
Fig. 11, of the clutch is bolted to
the flywheel of the engine and
rotates with it, carrying around
the driving*plates a. The shaft h
is coupled to the transmission of
the car. Under ordinary conditions, that is, when the clutch
pedal is not depressed, the spring k expands, forcing the
sleeve i and the web I apart and moving the ring / and the
adjusting nut m closer together. The disks a and b are thus
forced together and the rotary motion of the driving disks a is
imparted to the driven disks b. The driven plates b in turn
cause the inner member / to revolve and this turns the shaft h
that is coupled to the driving mechanism of the car. Thus,
power is transmitted from the engine to the propeller shaft when
the clutch is engaged. The clutch is disengaged by depressing
a pedal that forces the yoke n forwards, or toward the web /,

FicU

Digitized by

Google

TRANSMISSION AND CONTROL

§9

compressing the spring k. This movement forces the ring ; and
the nut m farther apart, thus relieving the pressure on the disks
and permitting the driving plates a to revolve without turning
the driven plates b. This disconnects the engine from the driv-
ing mechanism of the car and permits the motor to nm freely.
A gradual engagement can be obtained by allowing the pres-
sure of the spring to come gradually on the plates, so that the
driven disks will slip at first and then gradually speed up until
they have the same speed as the driving member. The clutch

Pig. 12

is adjusted by turning the nut m to the right or the left, thus
increasing or decreasing the tension of the spring when in the
engaged position.

20. The plates and adjusting nut of the Stevens-Diuyea
clutch are shown in detail in Fig. 12. Each driving disk is

Digitized by

Google

§ 9 MECHANISM 19

made up of a sted plate a faced on each side with wire-woven
asbestos fc, which is in four sections and is secured to the plate
by means of copper rivets. The rivets are coimtersunk in the
asbestos to prevent their heads from coming in contact with
the adjacent plates. The projections for holding the disks
in the cylindrical driving member are shown at c. The driven
clutch plates d are of plain steel and have projections e on the
inner circumference to prevent their turning on the driven
member of the clutch. When the clutch is assembled, the
adjusting nut / is locked in place by means of a lock pin that
passes through a hole g in the nut and a corresponding hole in
the inner clutch member. Several holes o, Fig. 11, are drilled in

Pig. 13

the inner clutch member, so that the nut can be locked in dif-
ferent positions. When turning the adjusting nut, it is necessary
to give it one and one-sixth revolutions each time, so that the
hole g. Fig. 12, will coincide with the holes drilled in the inner
member of the clutch. Other holes A, which do not pass clear
through the nut, accommodate a spanner wrench, by means of
which the nut can be turned.

21. Disk clutches employing cork inserts may be run dry
or they may be run in oil. When run in oil, the wear on the
corks is reduced but the coeflSdent of friction of the contact
surfaces is decreased at the same time. The Knox three-plate
dutch shown in Figs. 13 and 14 is an example of a dry-plate

Digitized by

Google

20 TRANSMISSION AND CONTROL §9

clutch with cork inserts, with the corks in the middle plate.
In Fig. 13, the clutch is shown disassembled; that is, with the
three plates a, 6, and c removed from the flywheel d. On
account of the small number of friction surfaces, the plates are
extra large to give the required area of friction surface. The
middle plate b contains the corks, which are arranged as shown.

Pio. 14

The clutch is of the multiple-spring type, the springs e being
contained in pockets in the flywheel d.

22* When assembled, as shown in the sectional view of
Fig. 14, the two forward plates a and b are located inside of
the flywheel d, and the plate c is bolted to the rim. Normally,
the clutch is held in engagement by the springs e, which force
the movable plates a and b against the fixed plate c. The

Digitized by

Google

§9 MECHANISM 21

plates a and c are the driving plates and rotate with the fly-
wheel, and the plate h is the driven plate and is keyed to the
transmission shaft/. With the clutch in the engaged position,
power is transmitted by friction from the driving plates to the
driven plate, thus forming a coupling between the engine shaft
and the transmission shaft.

The clutch is disengaged by a pressure on the foot-pedal
which is not shown in the illustration. A forward pressure on
this pedal rotates the shaft g, thus swinging the yoke ends h
forwards and sliding the sleeve i toward the flywheel. This
movement of the sleeve i swings the arms / on the pins k, which
in turn force the pins / forwards by means of the setscrews m.
Each pin / has a shoulder n that presses against the clutch
plate a; hence, when the foot-pedal is operated, the plate a is
forced forwards, compressing the springs e and separating the
friction surfaces of the clutch. This permits the engine to
run free, without rotating the driven plate and transmission
shaft.

The disk o. Fig. 14, belongs to the clutch brake. This disk
revolves with the transmission shaft while the disk p is sta-
tionary. When the clutch is disengaged, further movement
of the pedal forces the disk p forwards by means of the arms q
imtil it makes contact with the disk o and decreases its speed
and that of the driven member of the clutch. The part r is
the forward end of the transmission case.

23. Clutehes RmLntng in Oil. — ^The plates of a multiple-
disk clutch nmning in a bath of oil are not customarily faced
with friction fabric, although in some cases one set of disks is
provided with cork inserts. When metal-to-metal friction
surfaces are used, a greater number of disks is required than
when one set is faced with asbestos fabric, or is fitted with
cork inserts.

A tjrpical multiple-disk clutch designed to run in oil is the
Lozier clutch, which is made up of thirty-five hardened and
ground disks of saw-blade steel llj inches in diameter. These
disks are not faced nor provided with inserts of any kind but
are enclosed in an oil-tight case. The two sets of disks a and

Digitized by

Google

22 TRANSMISSION AND CONTROL § 9

b mounted in place on the inner spider c, are shown in Fig. 15.
Eighteen of these disks comprise the driving set, and when the
clutch is assembled they are rotated with the outer member d
by means of the keys e that engage with corresponding slots /
in the disks. The other seventeen disks make up the driven
set and are attached to the inner spider c. The closing spring
is shown at g and the pressure sleeve, by means of which pressure
is conveyed to the plates, at h. When the clutch is in use, the
outer member d is bolted to the engine flywheel, the cover i is
bolted to the outer member d, and the tnmnion, or collar, ;
surrounds the clutch shaft.

24. A sectional view of the Lozier clutch in its engaged
position is shown in Fig. 16. In this position, the driving disks a

Pig. 16

and the driven disks b are forced together by the pressure of
the closing spring c, which is compressed between the adjtisting
nut d and the closed end of the pressure sleeve e. The adjusting
nut d is screwed on the hub / of the cover g and is therefore
prevented from sliding in the direction of the clutch axis. The
tension of the spring can be adjusted by screwing this nut
forwards or backwards on the hub. The clutch is released
by a pressure on the foot-pedal, which is connected by a suitable
shaft and yoke to the collar A, so that a pressure forwards on
the pedal forces the collar toward the rear of the car, or away
from the clutch. The pressure of the collar is transmitted
through a ball thrust bearing i to the pressure sleeve and thus

Digitized by

Google

§ 9 MECHANISM 23

compresses the dosing spring c, allowing the disks to separate.
The driving disks a are free to slide on the keys ; and the
driven disks b on the keys k; hence, when the spring pressure is
released, these disks readily separate. As there is no connection
between the engine shaft and the transmission shaft other than
by means of the clutch plates, the engine runs without driving
the transmission when the clutch is not engaged. However, as
soon as the plates are forced together, motfon is transmitted

Fig. 16

from the fljrwhed through the plates to the driven drum I and
by means of the clutch coupling m to the transmission shaft n.
In this clutch, the end of the engine crank-shaft extends into
the clutch shaft where it rotates on the ball bearings o. A
spring p holds the oil ring q in place, thus preventing the escape
of oil from the clutch case.

222B— 34

Digitized by

Google

24 TRANSMISSION AND CONTROL § 9

Incorporated with this clutch is a clutch brake, which consists
essentially of a disk r that rotates with the transmission shaft,
and a stationary friction plate s that is forced against the disk r
when the clutch pedal is pressed forwards to its farthest
position. Friction between these two surfaces reduces the
speed of the transmission shaft so that the gears can easily
be shifted.

25. The disks of multiple-disk clutches running in oil have
a tendency to stick together when the clutch is released, especi-
ally when one set is provided with cork inserts. Therefore,
some means is often provided to insure separation of the disks
and thus prevent dragging of the clutch. A method some-
times used is to place smaU springs between the disks ; when the

Pio. 17

clutch is released these springs expand and force the disks
apart. An example of this method of releasing the disks is
foimd in the Premier cork insert clutch, shown in Fig. 17. The
driving disks a are of bronze and contain the cork inserts.
Each of these disks is provided with foiu- projections b that
engage with corresponding slots in the driving drum c, which
is bolted to the flywheel when the clutch is assembled. The
small springs d are placed between alternate driving disks to
allow room for them when the clutch is engaged. The driven
disks e are of steel and are provided with projections that

Digitized by

Google

§ 9 MECHANISM 25

engage with corresponding slots on the driven drum /. When
the clutch is disengaged, the small springs d force the disks a
and e apart and thus allow the driving disks to
turn freely between the driven ones.

26. Another method sometimes employed
to separate the disks of multiple-disk clutches
running in oil is to provide springs formed by
bending back strips partly cut from the metal
disk, as shown at a, Fig. 18. These bent-up
ends, or tongues, are formed on alternate disks,
usually the driving disks. When the clutch is
engaged, they flatten down, but when it is re-
leased, they spring out, forcing the plates apart.

In addition to overcoming the sticking tend-
ency of the friction surfaces, the separating
springs must overcome the frictional resistance
to the sliding of the disks along* the arms or
keys that drive them. If the clutch is transmitting considerable
power at the instant it is released, there is considerable fric-
tional resistance to the sliding of the disks along these parts.

CONTBACrriNG AND EXPANDING CLUTCHES

27. Band clutches making use of cylindrical friction
surfaces are used on a few makes of automobiles. The Haynes
clutch, which is illustrated in Fig. 19, is an example of the con-
tracting band type. In this clutch, which is shown in the
released position in view (a), the friction is obtained by tighten-
ing the steel band a around the steel drum 6. The band a is
keyed to a short shaft c, which is connected to the transmission,
and the drum b is bolted to the engine flywheel ; hence, when the
dutch is engaged, power is transmitted directly from the engine
to the transmission.

A peculiar feature of this clutch is the type and location of
the clutch spring d. This spring is attached at its upper end
to the lever e and at its lower end to some part of the automobile
frame, so that when it is allowed to contract, it turns the

Digitized by

Google

26 TRANSMISSION AND CONTROL § 9

clutch shaft /, which slides the collar g forwards by means of
the yoke h. The collar carries a wedge-shaped shipper head i,
which, when pressed forwards with the collar, forces the lever ;
to one side, thereby drawing the ends of the band a together and
engaging the clutch. The manner in which the lever / brings
the clutch in engagement is shown in view (6). Attached to the
upper end of the lever by means of a squared pin is a latch k

Fic. 19

that engages with a catch on the end of the strap /. As the
lever ; is swung to the left, it turns the latch k and draws the
strap toward it, tightening the band and engaging the clutch.

The clutch is released, or disengaged, by pressing forwards
on the foot-pedal m, which turns the shaft / against the expan-
sion of the spring d. The yoke and shipper head are thus
drawn away from the clutch, the lever ; takes the position
shown in (a), and the ends of the band a spring apart. The

Digitized by

Google

§ 9 MECHANISM 27

drum b is then free to rotate without turning the band a and
the engine can be run free.

At n is shown a roller bearing for supporting the shaft c, and
at 0 is the gear by means of which the shaft drives the trans-
mission gears. In some models of the Haynes clutch, the lever /
and latch k are held in the released position by a small helical
spring, which prevents any rattling of these parts. Adjustment
of the Haynes clutch is made by means of a setscrew p. The
clutch band can be tightened by screwing this setscrew into the
end of the strap /; and loosened, by unscrewing the setscrew.

28. In band clutches of the expanding type, the inner
member is of variable diameter and the outer member is a
drum attached to or integral with the flywheel. In this type
of clutch, the required friction is obtained by expanding the
inner member until its outer surface makes contact with the
inner surface of the outer member. As in the other types of
clutches, the inner member is connected to the transmission
shaft, so that when the clutch is fully engaged the engine
crank-shaft is directly connected to the transmission shaft.
The force of the clutch-closing spring ntiay be transmitted to
the expanding band either by means of levers or by a right-
and-left screw.

29. The clutch used on the Peerless car is an example of
an expanding band clutch employing a right-and-left screw to
expand the inner member. A perspective view of the inner
member of this clutch is shown in Fig. 20. The expanding
part is a steel band a that is covered with a leather facing 6 pro-
vided with cork inserts. The band is fixed at one end to the
clutch drum c and at the other, which is free from the drum,
to one end d of the expander arm. The dnmi contains a slot,
through which the band is secured to the expander arm by
means of a bracket. The other end e of the arm is attached to
the drum. Inside of the expander arm and nmning its entire
length is a screw that contains a right-hand thread at one end
and a left-hand thread at the other, which turn in corresponding
threads in the ends of the expander arm. This screw is turned
by the link/ and when this link is drawn toward the rear of the

Digitized by

Google

28 TRANSMISSION AND CONTROL § 9

car, or away from the clutch druin^ by the expansion of the
closing spring g, it rotates the screw in the direction that will
force the ends d and e of the expander arm apart and thus
expand the band a. As the band expands, the leather facing
takes hold of the inner surface of the flywheel drum, thus
engaging the clutch.

The clutch is disengaged, or released, by a pressure on the
clutch pedal, which, through a suitable rod, swings the operating
lever /t on its fulcrum at i and compresses the spring g by means
of the collar ;. This movement of the collar rotates the right-
and-left screw in the direction necessary to draw the ends of

Fig. 20

the expander arm toward each other and thus contract the
band a, allowing the flywheel to revolve freely. When placed
in the car, the fulcnmi i is carried on a pressed-steel bracket
that is attached to a side member of the frame.

30. A sectional view of the Peerless clutch and flywheel
showing the details of construction and the method of adjust-
ment is presented in Fig. 21. The expanding band is shown
at a; the leather facing, at 6; the inner drum, ate; the expander
arm, at d; the expander link, at/; the clutch spring, at g; and
the shifter collar, at /. The outer drum k is cast integral with
the flywheel. The engine shaft extends into the clutch shaft /
and turns on a bushing m and butts against a thrust bearing n.

Digitized by

Google

§ 9 MECHANISM 29

An endwise movement of the collar ; turns the right-and-left
screw 0 by means of the link/ and the adjusting screw p.

The clutch is adjusted by turning the screw p. A movement
right-handed rotates the right-and-left screw o to separate the
ends of the expander arm and thus tighten the clutch, while a
movement left-handed
rotates the screw o to
loosen the clutch.
The weight of the ex-
pander arm and screw
is compensated for by
means of a lead weight
q that is placed in the
inner dnmi directly
opposite these parts.

31. When a clutch
of the expanding type
is rotating, the cen-
trifugal action tends
to throw the expand-
ing portion outwards
from the center of the
clutch and thus in-
crease the pressure
between the friction
surfaces. At high
speeds, this increase of
pressure may become
great enough to make
the clutch hold much
tighter than it will at

low speeds. Hence, some means must be provided whereby the
expanding band, or shoe, will be positively withdrawn from the
outer drum when the spring is compressed. This is accom-
plished in the clutch shown in Figs. 20 and 21 by means of the
right-and-left screw. In other cases it is accomplished by means
of levers and togglejoints.

Digitized by

Google

30 TRANSMISSION AND CONTROL § 9

CLUTCH-OPERATING DEVICES

CLUTCH-ACTUATINO MECHANISM

32. Pedal Connections. — ^Friction clutches for automo-
biles are now invariably operated by a pedal that projects
upwards through the floor boards of the car and is within easy
reach of the driver's left foot. Generally, this pedal is carried
on a tubular shaft that extends part or all of the way across
the frame of the car and is supported by brackets on members
of the frame. This shaft also carries a yoke, by means of which
the clutch is released when the pedal is pressed forwards. In
the unit power-plant type of construction, the clutch pedal is
sometimes supported by a short shaft that is carried on the
clutch casing. Clutch pedals are attached in a variety of wa)rs.
Sometimes they are simply keyed or clamped to the shaft,
when they cannot be adjusted in any way. In other cases,
they are made adjustable and can be lengthened or shortened
within certain limits to suit the height of the driver of the car
and thus add to his comfort.

33. A simple form of clutch-actuating mechanism is shown
in Fig. 19 in connection with the Ha3mes contracting band
clutch. The pedal lever q is carried on the tubular shaft /
and is free to be adjusted to some extent. A hub r secured to
the shaft carries two lugs 5, between which is a lug t extending
outwards from the pedal. This lug t is held in place by two
setscrews that pass through the lugs 5, and its position, and
consequently that of the pedal, relative to the shaft, can be
changed by turning the screws. The pad m is secured to the
lever q by means of a bolt.

This clutch is designed in such a manner that it is released
by sliding the shipper head i toward the rear of the car. A
forward movement of the pedal turns the yoke backwards and
thus releases the clutch.

34. An example of a slightly different arrangement of
the clutch-actuating mechanism is shown in Fig. 22, which

Digitized by

Google

§ 9 MECHANISM 31

illustrates the mechanism employed on the Kline car. In this
dutch, it is necessary to press the inner cone a inwards, or
toward the flywheel 6, in order to release it. To accomplish
this, the cross-shaft c is mounted underneath the transmission
shaft d, instead of above, causing the yoke e to be moved ahead
when the pedal / is depressed. The cross-shaft is carried on
brackets secured to members of the frame. The clutch pedal /
is provided with an adjustment somewhat different from that
of the Haynes. The hub g, which is clamped to the shaft,
carries an arm h that extends in front of the pedal, as shown
at i, so that when the pedal is pressed forwards the arm is also

Fig. 22

moved. . The relative positions of the arm h and the pedal may
be varied by a setscrew ; that extends entirely through the
pedal lever, and against which the arm bears. A forward
movement of the clutch pedal revolves the shaft c, moving the
yoke e ahead and releasing the clutch.

The pedal k, located to the right of the clutch pedal, is used
for operating the service brake and is not connected in any way
with the clutch.

35. Adjustable Pedals. — The pedals used for operating
the clutch and service brakes are made adjustable for length
in a large nimiber of automobiles. Adjustable pedals are made

Digitized by

Google

32 TRANSMISSION AND CONTROL § 9

in a variety of forms and are, for the most part, quite simple
in construction. A common type is the bolt-adjustment
I>edal9 examples of which are shown in Fig. 23. In view (a),
which shows the practice followed in the Cole car, the shank of
the pedal is fastened to the pedal lever by a through bolt and the
pedal can be raised or lowered by making use of di£Eerent holes

Pig. 23

in the shank. In some pedals of this form two bolts are used,
while in still other cases the shank slides over the lever, which
is bent at approximately a right angle, as shown in (6), this
construction being used on Velie cars.

Another common form of adjustable pedal is the screw
pedal, illustrated in Fig. 24. In one form the pedal shank, or
spindle, screws into the tapped end of the
lever and a locknut is placed directly on
the shank, imdemeath the lever. This
is the practice of the Pierce-Arrow Motor
Car Company. In this design of pedal,
the pitch of the threads usually is not
very steep and the adjustment secured by
turning the pedal through one revolution
is close enough for all practical ptirposes.
In some pedals, a J aw-clamp adj ust-
ment is employed; that used in Pope-Hartford cars is shown
in Fig. 25. The end of the pedal lever contains a jaw clamp.
The shank of the pedal contains corrugations, or notches, in
which the bolt fits. The bolt passes through the jaws at the
end of the pedal lever and adjustment is made by removing the
bolt and sliding the desired notch in place.

Digitized by

Google

§9

MECHANISM

There are, of course, other designs of adjustable pedals than
those shown, but the principle is the same in all. Practically
the only di£Eerence is in the details of construction.

36. Some clutch pedals are constructed without any
of lengthening or shortening them, but the position
pedal itself can be changed, as shown in connection w:
clutch-actuating mechanism in Fig. 22. Another
device, which accomplishes this object, is shown in F

Pig. 25

Pig. 2<

and is used in some Overland cars. In this design, the
is attached to the shaft and the lever b is connected
hub by means of a bolt that passes through the slot c
pedal lever is free to revolve on the rod; hence, adjustr
made by loosening the nut and turning the lever to the <
position, after which the nut is again tightened. A not
feature of this pedal is that the face d can be tilted to an]
desired by loosening the nut in the pedal face and placir
the desired position. A considerable nimiber of manufa
make the pedal faces adjustable in this manner.

Digitized by

Google

34 TRANSMISSION AND CONTROL § 9

CLUTCH BRAKES

37. In order to eliminate noise as far as possible when
changing gears from a low to a higher speed, clutch brakes are
used extensively in modem cars. The clutcli brake is
simply a friction brake operated by depressing the clutch pedal,
its frmction being to bring to rest or to slow down the driven
member of the clutch when the clutch is released. Examples
of clutch brakes moimted on clutches are shown in Figs. 4, 14,
and 16. In each case the brake is so constructed that it is
applied when the clutch pedal is fully depressed.

38. A simple form of clutch brake, slightly different from
those already described, is used on the White automobile;

a perspective view of
the brake is shown in
Fig. 27. The mov-
able disk a is attached
to the inner member
of the cone clutch and
the stationary disk 6,
which is faced with
asbestos fabric, is sup-
ported from the frame
of the car by the
arms c and the cross-
tube d. When the
clutch is disengaged,
^°* ^ the plate a is carried

toward the rear by the inner cone and bears against the plate b.
The stationary plate is held against the movable plate a by
the springs e, thus obtaining the required friction. The adjust-
ing nuts / limit the action of the clutch brake. The driven
member of the clutch, and consequently the driving gears of
the transmission, can be slowed down or stopped entirely by
depressing the clutch pedal either partly or fully as desired.

39. In order to obtain the best results from the use of the
clutch brake, it is necessary to know when to use it and the

Digitized by

Google

§9 MECHANISM 35

extent to which it should be used for different conditions. The
transmission gears that are to be meshed when changing speeds
must have practically the same circumferential velocities in
order to make possible a silent shift; hence, for different con-
ditions the brake must be used in different ways. When start-
ing the car, the driven gears of the transmission are at rest;
therefore, the clutch pedal should be fully depressed so as to
apply the clutch brake fully and bring the driven member of
the clutch and the driving gears of the transmission also at rest.

When changing from a low to a higher gear, the driven gear
of the transmission is rtmning slower than the driving gear
that is to be meshed with it; hence, it is necessary to slow down
the driving gear but not to stop it entirely. This is done by
releasing the clutch but not fully depressing the pedal, or, in
other words, by partly bringing the clutch brake into operation.
Experience with any particular car is required to ascertain
exactly how far to depress the clutch pedal in order to obtain
the desired result.

When changing gears from a higher to a lower speed, the
clutch pedal should be operated so as not to bring the clutch
brake into action, because during this operation the speed of
the driving gear of the transmission is less than that of the
driven gear and any application of the clutch brake will decrease
it still further. The speed of the driven member of the clutch
and of the driving gear of the transmission can then be allowed
to increase with the engine speed while the gears are in neutral
until practically equal circumferential velocities of the meshing
gears are obtained.

FRICTION MATERIAIi9 FOB CLUTCHES

40. In cone clutches, the outer cone is generally made of
gray cast iron, malleable cast iron, or is a steel casting and the
inner cone is of alimiinum, cast iron, or pressed steel. The
inner cone is usually faced with leather or with some kind of
asbestos fabric, such as raybestos, multibestos, thermoid, etc.
Cork is also often used as a friction material in the form of
inserts in the leather facing. Metal-to-metal cone clutches have
been used to some extent but these are not employed at present.

Digitized by

Google

36 TRANSMISSION AND CONTROL § 9

When metal is used on leather or asbestos fabric, no lubrica-
tion of the rubbing surfaces is required; in fact, the presence of
a lubricant between these siuf aces is generally injurious and
detrimental to the operation of the clutch. However, a small
quantity of castor oil or neat's-foot oil is sometimes applied
to the leather of a slipping cone clutch for the purpose of putting
it in good condition. Before applying this oil, the leather should
be thoroughly washed in gasoline and then only a very small
quantity of cril used.

The friction disks of multiple-disk clutches, when entirely
of metal, as is tisually the case, are ordinarily of steel, or one
set of disks is of steel and the other set of bronze. In the former
case, the friction surfaces, erf course, are steel on steel, and in
the latter case, bronze on steel. Sometimes, one set of disks
is faced with asbestos fabric or provided with cork inserts.
The steel used to a considerable extent for the disks of friction
clutches is of the same quality as that used in common wood
saws and is known as saw-blade steel

In the case of expanding or contracting clutches, both friction
surfaces are sometimes steel, or one may be a cast-iron or steel
casting and the other brass or bronze.

Digitized by

Google

TRANSMISSION AND CONTROL
MECHANISM

(PART 2)

TRANSMISSION MECHANISM

SPEED-CHANGING MECHANISM

PUBPOfitB

1, Inasmuch as the gasoline engine will give its highest
eflSciency when working with ftdl charges, it shotdd be operated
under that condition as much as possible. Slight changes of
speed of the automobile and of the power of the engine can
be made by throttling and by manipulating the spark; but
for great speed changes, it is necessary to change the gear-ratio
between the engine and the driving wheels. The device used
for this purpose is properly called a change-speed gear, but,
popularly, it is known as a transmission. As the four-cycle
gasoline engine applied to automobiles is irreversible, it is neces-
sary, in order to go backwards, to change the direction of
rotation of the driving wheels by bringing into action a mech-
anism that will do this. This mechanism is called the revers-
ing gear, or reverse for short, and is incorporated in all
transmissions.

2. The change-speed gears in use on pleasure vehicles may
be divided into three general classes, depending on the principle
on which they operate. These classes are sliding change-speed
gears, planetary change-speed gearSy and friction transmissions,

corrmaHTBD by intbrnationai. tbxtbook company, au. maHTS rbbbrvbo

Digitized by

Google

38 TRANSMISSION AND CONTROL ' § 9

Several other types of transmissions have been designed from
time to time, but have never attained success commercially.

The speed-change mechanism is usually operated by the
driver by means of a lever or a pedal. However, a number of
cars are equipped with the electric gear-shift, in which the speed-
change mechanism is electrically operated, and is controlled
by means of push buttons located on or near the steering
wheel, or with the pneumatic gear-shift, which operates the
change-speed mechanism by compressed air.

SLIDING CHANGE-SPEED GEARS

3. Classification. — In the sliding-gear transmission, spur
gears are carried on two parallel shafts; one of these is in two
parts, a forward or driving part and a rearward or driven part;
the other shaft is a countershaft, or jack-shaft, through which
the power is transmitted for certain speeds. The various
speeds are obtained by sliding the gears axially on the main
shaft and securing the desired speed ratio by bringing them in
mesh with the proper gears on the countershaft. For what is
known as the direct drive, the two parts of the main trans-
mission shaft are locked together, forming a direct drive from
the engine to the rear axle. Sliding-gear transmissions are
ordinarily designed to give either three speeds forwards and
one reverse, or four speeds forwards and one reverse. The
former is popularly called a three-speed transmission, and the
latter dL four-speed transmission,

4. Sliding change-speed gears are constructed in two gen-
eral types, one of which is known as the selective transmission,
and the other as the progressive transmission. In the selective
transmission, the change can be made from any speed to any
other while the car is traveling, as from slow speed to high
speed; but in the progressive transmission, the change from
slow to high speed, as well as from high to slow speed, must
be made step by step through all the speeds.

There are two types of selective and progressive trans-
missions, namely, the horizontal and the vertical. In the
so-called horizontal transmission, the two shafts on which the

Digitized by

Google

§ 9 MECHANISM 39

change-speed gears are mounted lie in the same horizontal
plane, while with the vertical transmission the shafts lie in a
vertical plane, one above the other.

5. Vertical Tliree-Speed Selective Transmission.

The most widely used transmission system for pleasing cars
is the. three-speed transmission of the selective type. An
example of this system is the three-speed transmission shown
removed from its casing in Figs. 1 to 5, which is used in many
Northway unit power plants. In this system the cotmter-

shaft is mounted below the main shaft. The main shaft con-
sists of the driving part a, which carries the pinion 6, and the
driven part c, which carries the sliding gears d and e, and which
rotates in a roller bearing moimted within the pinion 6, and
another antifriction bearing at its rear end. The gears d and e
are free to slide axially on the shaft c, but are prevented from
revolving on it by four splines / that fit into corresponding
slots in the hubs of the gears. The sliding of the gears is
accomplished by the shifter forks g and /t, which are operated
by the change-speed lever acting through the shifter rods i

222B— 36

Digitized by

Google

40 TRANSMISSION AND CONTROL § 9

and y, respectively. The gears k, /, m, and n are fixed to the
countershaft o and revolve with it. The idler gear p is carried
on a short shaft of its own and is brought into use for obtain-
ing the reverse motion. The pinion 6 and the gear k are con-
stantly in mesh; hence, the countershaft always revolves when
the shaft a is in motion. The driving shaft a is connected
to the driven side of the friction clutch and receives its power
from the engine, while the driven shaft c is connected to
the propeller shaft and drives the differential gear and rear
wheels.

6. First, or low, speed is obtained by shifting the gear e
by means of the rod ; and the fork h until it meshes with the
gear m on the countershaft, as shown in Fig. 1. When in this
position, the pinion 6 drives the gear k, together with the
shaft o and the pinion m; the pinion m in turn drives the gear e
and the shaft c, which is connected to the propeller shaft. The
gear k on the coimtershaft is larger than the pinion ft, and there-
fore rotates at a slower speed. The speed of the pinion tn is,
of course, the same as that of k. The gear e, which is driven
by the pinion m, is l^ger than this pinion and consequently
rotates at a slower speed, which is the same as that of the
shaft c. There are, therefore, two steps in the reduction of
speed between the driving shaft a and the driven shaft c.
The first reduction of speed is between the pinion b and the
gear k, and the second reduction is between the pinion m and
the gear e. Both the driving shaft a and the driven shaft c
rotate in the same direction.

7. Second, or intermediate, speed is obtained by tmmeshing
gears m and e and shifting the gear d in mesh with the gear /
on the coimtershaft, as shown in Fig. 2. The coimtershaft is
driven at the same speed as before by means of the pinion b
^d the gear k. The gear / drives the gear d on the main shaft c.
The gear / is the same size as the gear d\ therefore, the latter
gearTotates at the same speed as the gear on the countershaft.
There is a reduction of speed from the pinion b to the gear k,
but no reduction or increase from the countershaft to the
driven shaft c. The result is that the propeller shaft rotates at

Digitized by

Google

§ 9 MECHANISM 41

a slower speed than the driving shaft a, but the total speed
reduction is not so great as in the low speed position.

While the gears / and d are the same size in the particular
transmission illustrated, this is not necessarily the case; some-
times the gear / is slightly smaller than the gear d, in which
case there is a slight speed reduction from the coimtershaft to
the driven shaft c. The gear / may also be larger than d, in
which case there is an increase of speed from the countershaft
to the driven shaft c.

8. In the third, or high, speed position the drive is direct
from the shaft a to the shaft c without going through the inter-

mediary gears on the coimtershaft. The gears are shown in
this position in Fig. 3. This setting is accomplished by sliding
the gear d forwards so that the clutch jaws q at the front end
of the gear engage with those on the rear end of the pinion b.
The transmission of power is now direct from the driving
shaft a through the jaw clutch to the driven shaft c. The
pinion b is still in mesh with the gear k, so that the counter-
shaft revolves, but no power is transmitted through it because

Digitized by

Google

42 TRANSMISSION AND CONTROL § 9

the gears /, m, and p run freely without meshing with either
gear d or e.

9. The position of the gears in reverse speed is shown in
Fig. 4. In this speed, the gear e is shifted to mesh with the
idler pinion p and the gear d is shifted to a position midway
between k and /. Power is transmitted to the coimtershaft
by means of the pinion b ond the gear fe, and through the shaft
to the gear n, which meshes with the pinion p. The gear n is
small enough in diameter to clear the gear e; it drives the gear e

by means of the idler p. The introduction of this idler causes
the gear e to revolve in the same direction as the gear n, which
direction is opposite to that of the shaft a and the driving
pinion b. In all the other cases that have been considered,
the driving shaft a and the driven shaft c rotate in the same
direction for forward travel of the car.

10. In the neutral position^ shown in Fig. 5, the gears are
set so that there is no connection whatever between the driv-
ing shaft a and the driven shaft c. The shaft a can be driven

Digitized by

Google

§9 MECHANISM 43

at full speed by the engine and the shaft c will remain station-
ary in this position. To obtain this setting, the gear e is shifted
to a position midway between the gears m and p, and the gear d
is shifted to a position midway between the gears k and /.
The pinion b drives the gear k as usual, but there is no connec-
tion between the coimtershaft and the shaft c; neither is the
jaw clutch q engaged. The gears are placed in this position
when it is desired to allow the engine to nm while the car is at
a standstill.

11. In order to secure accurate meshing of the gears as
well as to hold them in position, the shifting bars for selective

change-speed gears are provided with a locking device. This
device usually consists of a spring-operated plunger that drops
into a slot in the shifting bar for each position of engagement
of the gears. In Figs. 1 to 5, the plunger operating on the
shifting bax i is located beneath the plug r in the end member
of the housing and when the gears are shifted to neutral or
any other regtdar position, it drops into a V slot s in the
bar i. While these locks are not of suiBcient strength to

Digitized by

Google

44 TRANSMISSION AND CONTROL § 9

prevent the gears from being shifted by hand, yet they are
strong enough to serve the required purpose.

12. Three-Speed Progressive Transmission. — In the

selective transmission just described, the gears can be shifted
from any speed to any other speed without going through any
intermediate positions. For instance, a change can be made
direct from first speed to third or from third to first without
passing through second, or it can be made from third to neu-
tral without passing through either first or second. The pro-
gressive transmission differs from this, in that in changing from

first to third speed or from third to first, it is necessary to pass
throuojh second, and in changing from third to neutral, it is
also necessary to pass through second speed. In other words,
the various positions in the progressive system of transmis-
sion must be passed through in a fixed order. This is generally
considered a disadvantage; hence, the progressive transmission
is not so widely used as the selective.

13. A representative transmission system of the progres-
sive type is the Stevens-Duryea transmission, a top view of

Digitized by

Google

§9 MECHANISM 46

which is shown in Fig. 6. This system is of the horizontal type
and gives three speeds forwards and one reverse. The gears
are ^own removed from their casing, and the multiple-disk
clutch a and imiversal sliding joint b are seen in place to show
how the transmission is connected up. The arrangement of the
gears is exactly the same as in the selective transmission, except
that the two sliding gears c and d are connected by a sleeve, so
as to form one rigid part that is free to slide, but not to rotate,
on the shaft e. These sliding gears are operated by means of a
single lever /, which is pivoted near the middle and is in turn
operated by the driver of the car through a hand lever and

Pic. 6

connecting-rod. As in the selective gears shown, the gears on
the coimtershaft g are constantly revolving, the coimtershaft
being driven by the driving pinion h, which meshes with the
gear i and which receives power from the engine through the
clutch a,

14. The gears are shown in Fig. 6 in their neutral position.
The sliding gears c and d are not in mesh with any gears on the
countershaft and the jaw clutch / is not engaged; hence, no
motion is transmitted from the driving pinion h to the driven
part e of the main shaft. First speed is obtained by sliding the
gears c and d to the rear imtil the gear d meshes with the gear fe,

Digitized by

Google

46 TRANSMISSION AND CONTROL § 9

when the required speed reduction between the pinion h and
the shaft e is secured.

For second speedy the sliding gears are shifted forwards until
the gear c meshes with the gear /, in which case the speed
reduction is not so great as for first speed. The gears are in
highy or thtrdy speed when c and d are shifted still farther for-
wards and the jaw clutch ; becomes engaged with correspond-
ing slots in the hub of the gear c. Under these conditions, the
shaft e and the imiversal sliding joint b are driven directly
from the pinion h and, consequently, they revolve at crank-

FiG. 7

shaft speed when the clutch a is fully engaged. The counter-
shaft revolves as usual, but no power is transmitted through it;
on accoimt of this fact the gears run more quietly when in high
than when in any other speed.

By shifting the sliding gears completely to th-:; rear, the
reverse speed is secured. When in this position, the gear d
meshes with the idler gear w, which is revolved by the coimter-
shaft through the pinion n. The shaft e is therefore driven
in the same direction as the covmtershaft, but in the direction

Digitized by

Google

§ 9 MECHANISM 47

opposite to that from which the pinion h is driven, thus giving
a reverse motion to the propeller shaft.

15. Four-Speed Selective Cliange-Speed Mecha-
nism.— Selective change-speed gears giving four speeds for-
wards and a reverse are used on a number of the higher-priced
cars. In some the direct drive is on third speed and in some
it is on fourth speed. In Fig. 7 is shown the Winton four-speed
transmission, assembled in the bottom half of the casing. This
mechanism belongs to the class in which the clutch is contained
in the same case as the change-speed gear, and the direct
drive is on third speed. The general make-up and arrangement
of the gears is the sdme as in the three-speed type, except that
in the four-speed, there are more sliding gears and, consequently,
the shifting mechanism is slightly more complicated.

As in the preceding transmissions illustrated, the driving
pinion a, which is normally free from the main shaft fc, receives
its power through the clutch c. The power is transmitted to
the propeller shaft through the coupling d. The coimtershaft e
is revolved by the geaxf, which is constantly in mesh with the
pinion a. This pinion and the gear / are called constant-mesh
gears. Three shifter forks and three shifter rods are used for
shifting the gears on the shaft b. These are operated by means
of the speed-control lever, which has a sidewise motion so that
it can be engaged with any one of the rods.

16. In Fig. 7, the gears are shown in the neutral position.
First speed forwards is obtained by shifting the gear g forwards
until it meshes with gear h on the cotmtershaft. The main
shaft b and the propeller shaft are thus driven at a low rate
of speed and in the same direction as the pinion a. For second
speed forwards, the gear i is moved toward the rear until it
meshes with the gear ;. Third speed forwards is the direct
drive, the gear i and clutch member fe, which is in the form
of a spur gear, being moved forwards so as to mesh k with an
internal gear that is contained inside of the pinion a, and that
serves as the second clutch member. This setting gives a direct
drive from the pinion a to the coupling d without the use of
any gears, althmgh, as in the other mechanisms illustrated,

Digitized by

Google

48 TRANSMISSIO^f AND CONTROL § 9

the gears a and / remain in mesh and the countershaft e con-
tinues to rotate, but only idly. For high, or fourth, speed
forwards^ the gear / is moved forwards tmtil it meshes with the
gear m on the coimtershaft. As the speed ratio between the
gears m and / is greater than that between / and o, this setting
will drive the shaft fc at a greater speed than that of the
pinion a; hence, this speed is higher than that obtained on the
direct drive.

For the reverse speed, the gear g is shifted toward the rear so
as to mesh with the idler gear n. The idler gear is driven by
the pinion o; hence, when the gears are in this position, the
shaft b rotates in a direction opposite that^of the pinion a, and
the car is driven backwards.

Plungers for the shifting-bar locking device are located imder
the plugs p. When the gears are in position the plungers drop
into the proper slots, some of which are shown at q.

17. Hand Gear-Sblftlng Mechanism. — On automo-
biles having the steering column on the right side, the hand
lever for operating the change-speed gears is most commonly
located just outside the driver's seat on the right, with the
emergency brake lever to the right of the gear-shift leiver.
However, on some cars having the steering column on the
right, the control levers are located in the center of the car.
The objection to the latter arrangement is that the levers
must be operated by the left hand, which is generally not so
dexterous as the right. Many cars, and the number is increas-
ing, have the steering column located on the left side, when
the control levers are placed either on the left of the driver or
in the center of the car. The latter location is increasing in
popularity, because it permits the levers to be motmted directly
over the gear-box and thus does away with superfluous con-
nections, and at the same time it allows the driver to use his
right hand in shifting gears.

18# Fig. 8 shows a perspective view of part of the Series
Nine Cole chassis fitted with left-hand drive and center control.
The gear-shifting lever a and the emergency-brake lever b
are located directly over the transmission case c. The brake

Digitized by

Google

§ 9 MECHANISM 49

lever b operates in a quadrant d and is connected by the iisual
rods to a set of internal brakes on the hubs of the rear wheels.
The speed-change lever a operates in an H quadrant e, which
permits a sidewise as well as a forward and backward motion
for manipulating the shifter bars. This quadrant rises above
the floor board so as to be in plain view of the driver. When

Fig. 8

the lever is in one slot of the H quadrant, it is connected to
one of the shifter rods, and when it is moved sidewise to the
other slot, it immediately becomes connected to the other rod.
Hence, when the lever is moved backwards or forwards in
either slot it operates one shifter bar and thus slides the desired
gears in mesh and produces the required speed.

Digitized by

Google

50 TRANSMISSION AND CONTROL §9

The same general principle applies to cars having the con-
trol levers on the side, except that, of course, the connection
between the hand lever and the shifter rods is more extended.

19. There are two general methods by which the control
levers in the sUding change-speed gears of the selective type
are connected to the shifter bars, or rods. The first is by means
of a sliding shafts an example of which is the Pierce-Arrow
mechanism, shown in part section in Fig. 9.

In the speed-change mechanism illustrated, the control lever
is shown at a. Both sliding bars are shown in the end view
• at b and c, but only the bar c appears in the side view, because b
lies immediately back of it. The speed-control lever a is
fastened to a tubular shaft d that carries an arm e at the end
next to the shifting bars. This arm is shown in the side view
in engagement with the shifter bar c. The tubular shaft d
can be slid toward the right from the position shown in the
end view, so as to disengage the arm e from the shifter bar b
and bring it into engagement with the shifter bar c, or as shown
in the side view. The control lever a moves in slots in a quad-
rant/. These slots are so placed that the lever a can be pushed
forwards or drawn back only when it is in full engagement with
one of the shifter bars. The extent of the movement of the
control lever is restricted by the length of the slots in the quad-
rant. Thus, when the lever is thrown either full forwards or
back, the gears with which it is then in connection are set to
the proper position for the corresponding speed.

There are two. slots in the quadrant in which the control
lever moves when shifting the gears. When the lever is near
the middle of either slot, the gears are in neutral position.
The two slots are connected by an opening — corresponding to
the neutral position of the lever — so that the lever can be
shifted sidewise to engage either of the sliding bars when the
gears are in neutral position. The two slots and the opening
between them together appear much like the letter H. One
of the slots is elongated and is provided with a stop that ordi-
narily prevents the control lever from going more than the
proper distance to set the gears on slow speed forwards. In

Digitized by

Google

Digitized by

Google

TRANSMISSION AND CONTROL

§9

order to bring the control lever to the reverse position, it is
necessary to press down the piish button g at the top of the
control lever. This allows the lever to move far enough to
bring the reverse gears into engagement. The stop men-
tioned is useful, as it prevents the reverse gears from being
thrown into action accidentally when shifting the gears dur-

Pia 10

ing forward travel of the car, but is used in only a few makes
of cars.

20. The other method of connecting the control lever with
the gears in the selective change-speed mechanism is known as
the swinging-lever type. An example of this type is found on
some models of the Series Eight Cole automobile, the gear-shift-
ing mechanism of which is shown in Fig. 10. The emergency-

Digitized by

Google

§ 9 MECHANISM 63

brake lever a operates the shaft b and the shaft in ttim operates
the internal brakes on the hubs of the rear wheels through the
arm c and the proper connections. Two concentric tubes d and e
enclose the shaft b and transmit motion from the change-speed
lever / through the arms g and h to the shifter rods i and /,
respectively. These shifter rods, or bars, are the same as those
lettered i and ; in Figs. 1 to 5 and by referring to these illus-
trations in connection with the following, the movements of
the gears corresponding to the various movements of the
lever / can be determined. An arm k is attached to the outer
end of the tube e and a similar arm / is secured to the end of
the tube d. The lever/ is free to swing sidewise on its pivot m,
and by swinging it inwards, or toward the car, it may be made
to engage between two projections on the arm /?, and by swing-
ing it outwards it engages between two similar projections
on the arm /. The movement of the lever / is restricted by the
slots in the H quadrant. When the lever is in the inner slot,
it operates the arm k and when in the outer slot, it operates
the arm L Two flat springs, one on each side of the lever,
tend to keep it in a vertical position and hold it upright in
the central position in which it is shown, when it is moved to
this part of the quadrant.

21. With the control lever/ in the position shown in Fig. 10,
the gears are in the neutral position. First speed is obtained by
moving the lever to the rear of the inner slot in the quadrant,
or to the point marked 1. In thus shifting the lever, it engages
with the arm k and turns the tube ^ so as to shift the bar ; and
throw the slow-speed gear in position. Second speed is obtained
by shifting the lever/ to the forward end of the outer slot, or to
tiie point marked ^, In making this shift from the low-speed
position, the forward movement of the lever in the inner slot
disengages the low-speed gear, after which a sidewise motion
engages it with the arm I and a further forward motion in the
outer slot turns the tube d, thus shifting the bar i and mesh-
ing the second-speed gears. Third speed is secured by pulling
the lever / to the rear end of the outer slot, or to the point
marked S. In this position the gears are set for direct drive.

Digitized by

Google

TRANSMISSION AND CONTROL

§9

During the shift from second speed to third, the tube d and
shifter bar i are again brought into use. In setting for reverse,
the lever is brought to the forward end of the inner slot, or
to the point marked r. In this position, it again engages
with the arm k and operates the shifter bar /, as in the first-
speed position.

By passing from one slot to the other, the lever may be
brought to any position from any other position. This makes
the change-speed gears truly selective.

22. Selective-gear quadrants vary greatly in the arrange-
ment of the different gear positions, thus making it awkward
for a driver f amiUar with one make of car to drive another with
the gear positions differently arranged. However, efforts have

Pig. 11

b^en made by the Society of Automobile Engineers to remedy
this condition by making one arrangement a standard. The
preferred arrangements, with the positions marked, for three-
speed and four-speed gears of the selective type are shown in
Fig. 11. In view (a) is seen the arrangement for the three-
speed gears, the numbers representing the positions of the
lever for the several speeds forward and the letter i? indicating
the reverse position. In (6) is presented a quadrant for a four-
speed gear-set provided with three shifter bars like that shown
in Fig. 7. View (c) shows the preferred arrangement of a quad-
rant for a four-speed gear-set having but two shifter bars, the
sliding gears for reverse, first speed, and second speed being
operated by the same bar. A gear-set of this type is not truly

Digitized by

Google

§9

MECHANISM

selective, but is a combination selective and progressive gear-
set, because it is obvious that in order to change to the reverse
position, it is necessary to go through the first-speed position
from any other setting. The dotted line indicates a stop-
block that prevents the lever from
being accidently thrown into the
reverse position. With this type
of quadrant a latch must be with-
drawn before the gears can be
shifted to reverse. The word inside
represents the side of the quadrant
next to the driver, for left-hand
drive and center control, or right
hand drive and right-hand control,
and the word rear indicates the
end of the quadrant toward the
rear of the car.

23. In the progressive type of
change-speed mechanism, all the
speeds are obtained by a forward
and a backward movement of the
control lever; no sidewise move-
ment is necessary, because all the

sliding gears are shifted by means

of a single shifter lever. View (a),

Fig. 12, shows the arrangement of

the control levers on the Stevens-

Duryea car, model C-Six, viewed

from the right side of the car.

These levers are mounted outside

of the automobile frame and both

swing about the same center. The

brake lever a may be locked in any position by means of the

latch lock b that drops into the notches in the quadrant c.

The latch lock may be disengaged by means of the latch d.

The brake is applied, through suitable levers and rods, by

pressing forwards on the lever a.

222B— 36

Digitized by

Google

56 TRANSMISSION AND CONTROL § 9

The lever e is the change-speed lever and it operates in a
quadrant located immediately to the left of the quadrant c,
referring to its position in the car. A detailed view of the
speed-change quadrant is presented in view (6). The lever e

^^r^^^^^r^^^

Pic. 13

is provided with a stop / that is normally held in the notches
in the quadrant by the spring g, but that can be disengaged
by compressing the latch A. The arm i, which is operated by
a movement of the lever e, is connected by means of a rod to

Digitized by

Google

§ 9 MECHANISM 67

the shifter lever on the change-speed gears. The various
speeds are obtained by moving the lever until the stop drops
into the different notches. When the stop is at the extreme
rear end R of the slot in the qtiadrant, the reverse gears are
thrown in mesh. The first-speed stop is at i ; the second-speed
is at 2] the third-speed is at S; and the gears are in the neutral
position when the lever stop/ is in the notch marked N.

24. In a number of automobiles, there is incorporated a
device by which the speed-change gears and the clutch-actua-
ting mechanism are interlocked in such a manner that it is
impossible to shift the gears without first releasing the clutch,
or to engage the clutch unless the gears are in full mesh. With
a gear-shifting mechanism provided with such an interlock,
the gears are shifted in exactly the same manner as if no
interlocking device were fitted. The interlock acts without
any special attention from the operator of the car. The
advantage of this arrangement is that it prevents injury to
the gears from shifting them with the clutch engaged.

The interlocking arrangement incorporated in some models
of the Pierce-Arrow car is shown in perspective in Fig. 13.
One end of a rod a is attached to the arm b of the brake-opera-
ting mechanism and the other end carries a plunger c that is
moved forwards or backwards in a guide d when the clutch
pedal is depressed or released. A sector e is carried on the
control-lever shaft and it is provided with holes in its surface
into which the plunger c engages when the control lever is in
any of the various speed positions and the clutch pedal is
released. When in the neutral position, the plunger engages
in a slot running across the face of the sector and parallel with
the shaft. By this arrangement the control-lever shaft can-
not be rotated, and hence, the gears cannot be shifted unless
the clutch pedal is depressed and the plunger c withdrawn
from the hole or slot in which it is at the moment engaged.
Also, the clutch cannot be fully engaged imless the gears are
fully meshed and the sector is in one of the positions that will
permit the plunger to engage with a hole or the slot and thus
allow the clutch spring to act.

Digitized by

Google

TRANSMISSION AND CONTROL

§9

PLANETARY CHANGE-SPEED OEAB8

26. Deflnitionis. — In the planetary type of change-speed
gears, an arrangement of gears, known as an epicyclic train,
is employed for producing the various speeds. An epicydio-
gear train is a combination of gears in which a gear (or several
gears) turns on an axis that itself moves about a fixed axis.
On account of the similarity of this motion to that of the planets
around the sim, it is commonly called the suiuand-planet
motion. In a gear-set of this type, the driving member may
be a ring or wheel carrying the movable axis or axes, and the
driven member a gear on the fixed axis, or the arrangement
may be reversed. An epicyclic-gear train may be a combina-
tion of both spur and internal gears, when it is known as the
internal-gear type, or it may be made up of spur gears alone,
in which case it is known as the all-spur type. The latter type
is now used exclusively in pleasure-car change-speed gears;
hence, it alone will be dealt with here.

26. Principle of Operation. — ^A simple epicyclic-gear
train of the all-spur type is shown diagrammatically in Fig. 14.

An arm a joins the
two gears b and c and
holds them in mesh.
The axis d of the gear
b is fixed, but the arm
a is free to revolve
around this axis and
carry the gear c bod-
ily with it. Suppose
that the gear b is held
stationary and the
arm a is turned in the direction of the arrow about the axis d.
The gear c is then carried bodily arotmd the axis d and at the
same time it rolls on the gear b and turns on its own axis e.

27. By adding more gears to the simple train shown in
Fig. 14 a combination can be obtained whereby the driven
member may be made to rotate at different speeds by holding

Fig. 14

Digitized by

Google

§9

MECHANISM

different gears stationary. Fig. 15 shows a reverted gear^ain
such as is utilized in the planetary system of speed-change
gears. However, this illustration does not show a complete
speed-change mechanism, but simply shows the prindple
involved. The gears a and b are free to revolve about the

Fig. 16

common axis c, which is immovable. Meshing with a and b
are two pair of gears consisting of two gears each, d and e,
that are fixed to each other and revolve together. The gears d
and e are mounted on a ring that is free to move; hence,
these gears not only turn on their own axes, or centers, but

Digitized by

Google

60 TRANSMISSION AND CONTROL § 9

they can be carried bodily around the gears a and b by revolv-
ing the ring/.

With the arrangement of gears shown in the illustration,
the following planetary motions may be obtained:

First, assuming that the ring is the driving member and the
gear b the driven member, a slow speed forwards may be
imparted to the gear b by holding the gear a stationary and
revolving the ring. During this operation each gear d rolls on
the gear a so that it turns on its own axis and at the same time
moves bodily arotmd the fibced center c. Each gear e, being fixed
to the gearsd, is carried about with them and being in mesh with
the gear 6, it imparts a certain motion to 6. Eadi gear e being
smaller than d, the velocity of its teeth is less; hence, as it
moves around the center c, the gear b is turned slowly in the
same direction as the ring /. The relative speeds of the gear b
and the ring depend on the relative sizes of the gears a and d
and the gears b and e.

Second, assvuning that the ring is the driving member and
the gear a is the driven member, a motion in the opposite
direction to that of the ring may be imparted to the gear a by
holding the gear b stationary and revolving the ring. During
this operation, each gear e rolls on the gear 6, as the ring is
tiuTied, and carries d about with it. In this case, as the teeth
of the gears d have a higher velocity than those of the gears e,
the gear a is slowly turned backwards, or in a direction opposite
to that in which the ring revolves.

28. Two-Speed Planetary Transmission. — ^The rep-
resentative planetary transmission is the Ford all-spur system,
used in the model T car, which is designed to give two speeds
forwards and a reverse. The manner in which the reverted
epicyclic-gear train is applied to this gear-set is shown in
Figs. 16 and 17, Fig. 16 being an external view and part section
of the transmission in its case, and Fig. 17 a sectional view of
the system removed from its case. Like parts in the two illus-
trations are lettered the same as far as possible.

The driving member in this case is the engine flywheel a.
The flywheel carries t)n studs three clusters of three gears each.

Digitized by

Google

Digitized by

Google

Digitized by

Google

Pig. 17

Digitized by

Google

Digitized by

Google

§9

by c, and d; these gears
ttim on the studs. Tl
intervals around the fl;
groups mesh with three
ported by an extension -
The gear e is the driver
forms the hub of the cl
the propeller shaft by
shaft, ; and a universal j
the propeller shaft revo
the hub of the drum k, 2
Each drum is sur-
rounded by a band as
shown in Fig. 16, by
means of which it may
be prevented from
rotating. The band
surrounding the drum
i is utilized simply as
a brake band for slow-
ing down or stopping
the car, while the
bands surroimding the
drums k and / are
brought into use for
obtaining a reverse
or slow speed. The
clutch drum contains
the multiple-disk clutch
engine-shaft extension J
uo drive the propeller si

29. Low speed forv
speed gear by tightenin
drum k, thus preventin
gears c, carried around
turn the gears b and d
gear e from 6, and as b

Digitized by

Google

62 TRANSMISSION AND CONTROL § 9

this motion is in the same direction that the flywheel revolves,
but at a slower speed. The propeller shaft being directly con-
nected to the gear e, is, therefore, driven at a slow speed in the
direction of rotation of the engine crank-shaft, and a slow
speed forwards is imparted to the car. During this operation,
the gear g and the drum / are driven idly by the three gears d.

The reverse speed is obtained by releasing the band on the
drum k and tightening that on the drum /. This operation
prevents the gear g from revolving and causes the three gears d
to roll about g. The gears h and c are of course carried around
withd; hence, a reverse motion is imparted to e, because the
gears h have a larger number of teeth than the gears d. The
propeller shaft is, therefore, rotated in a direction opposite
to that in which the flywheel revolves, and the car is driven
backwards. During this operation the gear /and the drum k
are driven idly by the three gears c.

High speed forwards is obtained by engaging the multiple-
disk clutch m, thus locking the shaft k and the clutch drum i
together and driving the propeller shaft at the same speed as
the engine shaft revolves. The clutch is held in engagement
by means of the spring n, which surroimds the sleeve ; and forces
the disks together by means of the sleeve o and the levers p.

When assembled on the car, the various bands and the clutch
are operated by a single lever and three pedals, which are con-
nected up through suitable operating mechanism.

FBICnON-OEAB TRANSMISSION

30. The friction-gear transmission makes tise of a
friction disk and a friction wheel running at right angles to
each other for changing the speed of the car in relation to the
engine speed. The friction units are so arranged that a sepa-
rate friction clutch is unnecessary; the engine can be discon- "
nected from the transmission mechanism by withdrawing the
disk from the wheel and allowing the disk to run idly. With
this speed-change gear, an infinite number of speeds may be
obtained by var>'ing the point of contact between the friction
wheel and the disk.

Digitized by

Google

§9 MECHANISM 63

31. A typical example of the friction-gear transmission
is the Cartercar system, which is shown in Fig. 18. In this
transmission, the friction disk a, which is driven by the engine,
drives the fiber-faced wheel 6, which, in turn, propels the rear
axle by means of a chain that is enclosed in an oil-tight case c.
The disk a is connected to the engine by a short shaft con-
taining a sliding connection that allows the disk to be engaged
with the friction wheel by a pressure on the pedal d. The
wheel h is mounted on a transverse shaft e in such a manner
that it can be made to move across the face of the disk a from
one side to the other and drive the shaft e in any position.

The friction wheel h is shifted by a bell-crank / connected to a
crank-arm g of the control lever h. The bell-crank is pivoted
to a bracket i and carries a drag link ;, through which the
wheel is moved.

As the linear speed of points at different distances from the
center of the disk a varies from zero at the center to a maxi-
mtmi at the periphery, or outer edge, the rotative speed of
the friction wheel depends on its distance from the center of
the disk. Thus, to obtain a slow speed, the friction wheel 6
is shifted toward the center of the disk a by a rearward

Digitized by

Google

64 TRANSMISSION AND CONTROL § 9

movement of the control lever h, and to obtain higher speeds
it is shifted toward the periphery by a forward movement of
the lever. To obtain a reverse, the friction wheel is shifted
past the center of the disk a, when the direction of rotation
of the wheel, and hence of the driving wheels of the car, is
reversed. The neutral position is obtained by simply releasing
the pedal, when the disk is free to revolve without trans-
mitting motion to the friction wheel. In this car the action
of the pedal d is the opposite of that of the clutch pedal in
the ordinary sliding-gear change-speed mechanism. Depress-
ing the pedal d engages the friction disk and wheel and
starts the car. A locking device is provided by means of which
the friction surfaces can be held in contact without keep-
ing the foot on the pedal.

32. The electric starting motor, which furnishes power for
cranking the engine, is shown at k, Fig. 18. This motor is
connected to the shaft running from the engine to the friction
disk by a silent chain that is encased in an oil-tight case /.
The emergency-brake lever is shown at m and the service-brake
pedal at n. These are operated as oh any other car.

Various forms of friction-gear transmissions have from time
to time been devised, but that employing the disk and wheel
as just described is practically the only one now in use on
pleasure vehicles. A system very much the same as that shown
in Fig. 18 is used on the Metz car; in this case, however, a
double chain drive is employed between the cross-shaft and
the rear axle.

ELECTRIC OEAB-SHIFTINO MECHANISM

33. The sliding change-speed gears thus far described are
designed to be operated manually by a lever. With the electric
gear-sliifting: meclianisin, the work of changing the speeds
is accomplished by means of electromagnets having the form
of solenoids with a movable core, instead of by hand. By
solenoid is meant an electromagnet consisting of a coil of
insulated wire wotmd helically around a cylindrical soft-iron
core, which becomes magnetized as soon as an electric current

Digitized by

Google

§9 MECHANISM 65

is sent through the coil of wire. The particular form of sole-
noid used in the electric gear-shift has a hollow cylindrical coil
of wire that surrounds a cylindrical iron core free to move in
the direction of its length, the coil of wire being stationary.
If the iron core is partly withdrawn from the coil and an elec-
tric current is sent through the coil, this will attract the iron
core and tend to draw it back inside the coil.

The electric gear-shift as applied to the sliding-gear type of
transmission, has one solenoid for each speed forwards, and
one for the reverse. The operation of the solenoids is controlled

j rW Pic. 19

by means of a push-button switch, or selector, located on the
steering wheel, and a master switch that is operated by
the clutch pedal.

34. The Vulcan electric gear-shift as applied to the
Haynes, .models 26 and 27, cars is shown mounted on the
chassis in Fig. 19. The shifting mechanism, which is here
viewed from the left side of the car, is contained in a separate
housing a and is located on top of the change-speed gear
casing. The transmission on this car is of the selective sliding-
gear type, giving three speeds forwards and a reverse; hence,

Digitized by

Google

66 TRANSMISSION AND CONTROL §9

four electromagnets, or solenoids, 6, c, d, and e are required for
manipulating the speed changes. The neutral position of the
gears is mechanically obtained by depressing the clutch pedal/,
which is connected to the shifting mechanism by the link g.

As shown in Fig. 20, in which the mechanism is viewed from
the right side of the car and with the cover removed, the gears
are shifted, just as in the hand-operated mechanism, by means
of two shifter bars, one of which is shown at fe, that are drawn
endwise by the magnetizing of the solenoids. When the low-

FiG. 20

speed solenoid b is magnetized, a pull of 150 pounds is exerted
on the corresponding shifter bar and it is drawn forwards,
shifting the gears through an ordinary shifter fork. As soon as
this operation is completed, the current is cut off from the
solenoid and the gears remain in mesh as in the hand-operated
system, until another change is desired, or until the gears are
thrown into neutral by means of the clutch pedal. The action
of the other solenoids is similar to that of the low-speed mag-
net; the solenoid c pulls the gears into second speed, d pulls
them into third, or high, speed, and e pulls them into the
reverse position.

35. The speed-change gears on the Haynes car are shifted
from any position into neutral mechanically by means of the

Digitized by

Google

§9 MECHANISM 67

yoke i in Fig. 20, which extends crosswise above and below the
shifter bars and is pivoted at each end so that it is free to
rotate. However, the yoke tends to remain in the central
position shown, being restrained by means of a mas
or spring, contained in the casing ;. Each shifter bar
with two lugs, or stops, one above and one below, one c
always engages with the yoke i when a gear-shift i:
pulling it around in a clockwise direction, as viewed in
and against the resistance of the master lock ;.

Referring to Fig. 19, the shaft k carries a latch jus
of the casing a, by means of which the yoke i, Fig. 20, i
when the clutch pedal is depressed. For instance, w
gears are shifted to the reverse, the solenoid e draws tl
forwards, at the same time engaging the lug / with th(
and pulling it around. The gears can then be thro^
neutral by a pressure on the clutch pedal, which revo
latch on the shaft k, Fig. 19, and thus brings the yoke
its center position, pulling the bar h and the sliding g(
it. Just as the yoke reaches this position, the stationar
trips the latch, so that the yoke is again free to be
by some other lug. The latch, of course, assumes its
position when the clutch pedal is released.

In the case of the second-speed gear-shift, the lug fi
extends below the bar h, engages with the lower pari
yoke i and turns it in the same direction as it was tu
the lug /; hence, the action of the latch when the clutc
is depressed is identical to that in the case of the rever
shift.

A similar action occurs when the other solenoids, b
are brought into use, the shifter bar in this case being cc
by the casing a; one of the lugs, however, is shown at
account of an interlocking device in the push-button
or selector, it is impossible to magnetize more than o
noid at a time; hence, there can be no conflict in the a
the electromagnets.

36. In the event of a failure of the electric gear-shifting
mechanism to work, or if for any other reason it is desired, to

Digitized by

Google

68 TRANSMISSION AND CONTROL §9

shift the gears by hand, a control lever may be inserted in the
slot p, Fig. 20, by removing the cap g. Fig. 19, which extends
upwards through the floorboards of the car. The lever can
then be used like the ordinary control lever for a selective-
transmission system.

37. The arrangement of the selector push buttons on the
steering wheel of the Haynes is shown in Fig. 21. The selec-
tion of the desired gear-change is made with these buttons
and each one is plainly marked to show the speed that it con-
trols, as shown. The button that is used for securing first, or

low, speed is marked
1 ; that used for second
speed is marked 2\
that for third, or high,
speed is marked S\
and that for reverse
is marked R, The
neutral position is
selected by means of
the button marked A/".
The buttons H and S
operate the electric
horn and starting
motor, respectively.

On some cars, the

buttons are arranged

in a straight line on one of the spokes of the steering wheel,

while in other cases they are arranged on a switch directly

beneath the wheel.

Current for magnetizing the solenoids is obtained from the
storage battery used in coimection with the electric lighting
and starting system. The master switch, by means of which
the proper solenoid is finally put in electrical connection with
the battery, is mechanically operated by the clutch pedal;
pushing the pedal all the way down engages this switch and
magnetizes the solenoid selected by the selector on the steering
wheel. The master switch is located between the clutch shaft

Digitized by

Google

§9

MECHANISM

and the shifting mechanism. It is made in a variety of forms,
but usually consists of a simple knife switch that is engaged
by means of a cam that is rocked by the clutch shaft.

38. A simple wiring diagram for the electric gear-shift
is shown in Fig. 22, where the solenoids are marked the same
as in Figs. 19 and 20. The master switch r is common to all
the solenoids, but in order that a solenoid may be magnetized
it is also necessary that electrical coimection be made at the
corresponding button. The neutral button iV is not coimected
in the circuit, but when pressed, it releases all the other buttons;

/& — s— a — a — W[

n n n

^:.

Fig. 22

that is, opens the circuit at each one. The buttons are pro-
vided with a mechanical interlock so that one button only can
remain in position at a time.

39. With the engine running and the gears in the neutral
position, a shift to first speed is made with the electric gear-
shift by pressing down the first-speed button and then closing
the master switch by pressing the clutch pedal clear out. The
first-speed solenoid becomes magnetized and the gears are
drawn into the first-speed position, after which the clutch
pedal may be released and the clutch engaged in the usual
manner. Any other speed change may be made by pressing
down the required button and then pushing down the clutch
pedal. Each time a change is made the clutch is first released
and then the gears are thrown into neutral by the mechanical
coimection to the clutch pedal, which has been previously

Digitized by

Google

70 TRANSMISSION AND CONTROL §9

explained ; hence, there is no danger of shifting gears with the
clutch engaged and thtis stripping gears. The gears can be
thrown into neutral at any time by pressing in the neutral
button and pushing the- clutch pedal forwards, although in this
operation it is only necessary to push the pedal far enough
to mechanically shift the gears, it not being necessary to close
the master switch, as there is no neutral solenoid.

40. With the electric gear-shift, the clutch may be released
at any time by shoving the pedal forwards part way without
disturbing or changing the setting of the speed-change gears.
When driving on a certain speed, the driver may at any time
select the next speed to which he wishes to change and press
down that button. He can then make the change when he
desires by simply pressing forwards on the clutch pedal and
then releasing it.

PNE!UMATIC GEAB-SHIFTINO MECHANISM

41. The pneumatic gear-shifting meclianisni, as the

name implies, makes use of compressed air, instead of hand
power or electricity, for shifting the speed-change gears. The
Gray pnetunatic gear-shifting device, which can be applied
to many cars that are fitted with a sliding-gear transmission,
is shown partly in section in Fig. 23. The air presstu-e for
operating this device is obtained from a double-acting, two-
cylinder, air compressor that is located alongside of the engine.
The compressed air is stored in a tank located under the body
of the car. An air pressure up to 300 pounds per square inch
is automatically maintained in the tank.

42. Referring to Fig. 23, the main casting a is bored out,
forming a cylinder in which a piston 6 works. A sliding dis-
tributor valve c regulates the admission of the air to the cylinder
and the exhaust from it. There is but one intake connection d,
which is controlled by the valve e; this valve is in turn lifted
by the bell-crank / that is operated by the rings on the distrib-
utor valve c. A single exhaust passage g provides a way of
escape for the air from each end of the cylinder.

Digitized by

Google

§ 9 MECHANISM 71

A selector disk h carrying a latch i is operated by the piston 6,
being rigidly attached to the piston rod and outside the cylin-
der a. This disk h is free to slide endwise on the shaft ; but is
keyed to it so that it can be tiuned by rotating the shaft. The
latch i can be tiuned by the shaft ; and made to engage with
notches in the shifting racks k and /. The racks k are connected
to the shifting bars of the regular speed-change mechanism.
With the ordinary three-speed gear-set only two of these racks
are used, but with a
four-speed gear-set all
the racks are used.
The racks I are idler
racks, by means of
which the motion of
the two outer racks k
can be reversed
through connecting
pinions, one of which
is shown at m.

43. Gear shifting
is accomplished by the
device shown in
Fig. 23, by engaging
the selector latch i
with the notch in the
required shifting rack
and forcing the rack

forwards by the ^'°-^

admission of air into the cylinder. The selector shaft / is
coimected to the selector quadrant on the steering colimin
and the desired gear is selected by turning the selector shaft
so that the latch i engages the rack operating the particular
gear selected. The sliding valve c is drawn forwards by depress-
ing the clutch pedal to which it is attached by a cable or rod.
The valve is moved to its original position by the spring n
when the clutch pedal is released, after the gears have been
shifted.

222B— 37

Digitized by

Google

72 TRANSMISSION AND CONTROL §9

A shift is made to any speed by first selecting that speed by
means of the selector quadrant and then depressing the clutch
pedal all the way and releasing it. A half depression of the
clutch pedal admits air to the selector end of the cylinder at
the instant the clutch is fully disengaged and forces the gears
to the neutral position by means of the selector disk h. Each
shifter rack is made with a shoulder and on this movement of
the piston, that rack that is not in the neutral position is shifted
back into it by the disk engaging with the shoulder. The full
depression of the clutch pedal opens the exhaust passage from
the selector end of the cylinder and at the same time admits
air into the other end. The piston is then forced forwards
carrying with it the particular shifting rack engaged by the
selector latch i.

44. The advantages of the pneumatic gear-shifting mecha-
nism are practically the same as those of the electric gear-shift.
Any gear-shift can be made without removing the hands trom
the steering wheel. Also, as in the electric gear-shift, the gears
are always brought to the neutral position before a shift is
made, and, likewise, the clutch must always be disengaged.
This obviates the danger of shifting gears with an engaged
clutch.

A hand lever is furnished with this gear-shifting device to be
used in case the pneimiatic mechanism becomes inoperative
for any reason. The hand lever is tised by connecting it to the
collar 0 on the selector shaft and thus shifting the disk h.

TWO-SPEED BEVEL-GEAB REAR AXLE

45. In the ordinary rear-axle construction there is a fixed
ratio between the speed of the drive shaft and that of the axle.
A bevel pinion on the end of the propeller shaft or, in the case
where the speed-change gears are located at the rear, on the
end of the transmission drive shaft, meshes with the large
bevel driving gear on the differential and drives it at a constant
speed ratio. The ratio between the speed of the engine and that
of the rear wheels when nmning on direct drive is always the
same with this arrangement.

Digitized by

Google

§ 9 MECHANISM 73

In order to secure more than a single speed raf io on direct
drive and thus make a more flexible transmission, the two-
speed direct-drive rear axle is being used in some cars. This
device makes use of two bevel pinions of different sizes that
mesh with two bevel driving gears on the differential. Either
one of the bevel-gear sets can be brought into use by the
driver, so that two distinct gear-ratios are available. This
device in no way affects the regular change-speed gears; hence,
six different speeds forwards can be obtained with an ordinary
three-speed transmission and a two-speed axle, or eight speeds
can be obtained with a four-speed gear-set.

46. The two-speed rear axle used on some models of the
Cadillac car is shown in' perspective in Fig. 24 and in section

Pic. 24

in Fig. 25. Referring to Fig. 24 the bevel pinions are shown at
a and b in mesh with the bevel driving gears c and d, respec-
tively. These four gears are always in mesh, as shown, but
the driving-mechanism arrangement is such that but one pinion
can receive power from the engine at a time. The large gears c
and d are both attached to the differential, and the rear axle
can be driven equally well through either one. The low-speed
ratio, or that between the gears b and d, is 3.66 to 1, while the
high-speed ratio, or that between the gears a and c, is 2.5 to 1.

Digitized by

Google

74 TRANSMISSION AND CONTROL §9

47. The bevel pinions are driven from the propeller shaft
through a jaw clutch e. Fig. 25, which can be made to operate
only one pinion at a time. This clutch is in the fonn of an
internal gear driven from the propeller shaft and is so arranged
that it can be engaged either with the clutch member /" resem-
bling a spur gear on the end of the hollow shaft g carrying the
small pinion 6, or with the clutch member h on the end of the
sleeve i that carries the large pinion a. The clutch e is free to
slide on the extension / of the propeller shaft, but is prevented
frx)m rotating on it by means of splines. The hollow shaft g
tiuTis on Hyatt roller bearings k that are mounted between
this shaft and the shaft / , while the outer sleeve i turns on Tim-
ken roller bearings / that are mounted between this sleeve and
the housing. For shifting the jaw e forwards or backwards a
shifting shaft m is provided. This shaft carries a yoke n that
engages with the clutch e and transmits the motion from the
shifting shaft to the clutch. An ordinary bevel-gear differen-
tial 0 is employed for driving the rear axle.

48. The jaw clutch for changing the speed ratio of the
driving gears in the Cadillac two-speed rear axle is operated
by means of the regular engine-dutch pedal used in conjunc-
tion'with an electric switch that is located on the right front
door of the car. The pedal is connected by suitable levers and
rods to the shaft m. Fig. 25, and is used for actually shifting the
jaw clutch, while the electric switch controls a magnetic latch
that does the selecting of the gear combination.

For instance, if it is desired to make use of the high-speed
ratio, the switch lever is held forwards and the clutch pedal is
depressed. For changing to the low-speed ratio, the switch
lever is hold back and the clutch pedal depressed. Under the
first condition, the jaw clutch is engaged with the clutch mem-
ber h and the differential is driven through the pinion a and the
bevel gear c, while under the second condition, the jaw engages
with the clutch member / and the small pinion h and the bevel
gear d are brought into use. Because of the construction of the
jaw clutch, it is impossible to drive both bevel pinions at the
same time.

Digitized by

Google

75 Pig. 25

Digitized by VjOOQ IC

76 TRANSMISSION AND CONTROL § 9

POWER TRANSMISSION DETAILS

UNIVERSAL JOINTS

49. Main-Drive Couplings. — The universal joint, or
coupling, is a coupling used to connect two shafts, the center
lines of which are in the same plane, but which make an angle
with each other. In an automobile fitted with a shaft-drive
rear axle, one or more imiversal joints must be provided between
the engine and the rear axle, in order to make up for lack of
alinement between the engine and the axle, due to construction,
and also for disturbance of alinement due to play of the springs.

In addition to providing for lack of alinement, it is necessary
on a propeller-shaft drive to make provision for any variation

in the distance between
the change-speed gears
and the rear axle or
between the clutch and
the change-speed gears,
I as the case might be,
' occasioned by the play
of the rear springs. In
practice, this is allowed
for either by construct-
ing the universal joint
so that it permits a
^- ^ certain slip within itself,

or by providing the joint with a sliding connection, or slip sleeve.

50. One of the most widely used types of imiversal joints
is the cross type, one form of which, as made by the Blood
Brothers Machine Company, is shown in Pig. 26. The joint
consists of two forks a and 6, and a cross formed of two mem-
bers or pins, one passing through a hole crosswise in the enlarged
portion of the other, and both passing through a center block c.
One of the pins is shown at' d. The pins turn in bushings e,
which are of hardened steel, one end being forced into the holes
in the forks while the other projects outwardly to form a longer

Digitized by

Google

§ 9 MECHANISM 77

bearing surface, and is threaded for the grease caps /. The
center block c is a steel cube that fits between the forks and
serves to center them and keep them in adjustment. The forks
a and b are intended to be keyed or brazed to the ends of the
shafts that they connect, or one fork may be provided with a
sliding joint that allows endwise motion of the propeller shaft.
The fork a is free to turn on the cross-pin d, and the fork b
on the pin at right angles to d, thus forming a flexible coupling
that may be used
to connect two
shafts that make an
angle with each
other.

51. The method
of assembling the
pins and center
block in the tmi-
versal joint just de-
scribed is shown in
Fig. 27. The pin a
passes through a
hole in the pin 6,
which is enlarged
in the middle as
shown in view (6).
This prevents the
enlarged pin from
moving endwise.

The smaller pin a is ^''' ^

locked by a third pin c, which passes longitudinally through the
center of b and crosswise through a. A bushing with its grease
cap is shown in place at d, view (a). A felt washer e is placed
between the bushing d and the center block / and prevents the
oil or grease from coming out and the dust from getting in.

The joint can be disassembled by taking off the grease caps
and then withdrawing the pins c and a. In order to take out
the enlarged pin, one of the steel bushings must be removed.

Digitized by

Google

78 TRANSMISSION AND CONTROL § 9

52. A Spicer universal joint, which is of the ring type, is
shown partly disassembled in Fig. 28. The four bearing pins
are carried on a journal piece, or ring, a that serves to join the

jl forks b and c. Each

Piilllilk journal turns m a

■ "^^61^ hardened-steel bush-

I 11 ing d. When assem-

llirfjSiiiill '^^^^» ^^ casing e is

■HH bolted to the flange/

^^HHV and the casing g fits

^^n^^ over the end of the

casiQg e. The casing g
is held in place by
means of a clamp that
is screwed on the end
of the fork 6. The
joint is lubricated
through a hole that is
normally closed by a
screw h. A sliding
connection may be attached to the yoke fe, in order to provide
for any endwise motion.

53. A universal joint of the roller type, such as is used in
some models of the Peeriess car, is shown in Fig. 29. A cross a
on the end of the propeller shaft carries two rollers b, which
roll in steel yokes c in the

other half of the joint.

The cross and rollers are

shown withdrawn from

the yoke. The joint is

normally protected from Prc. 29

dust by a telescoping leather and altuninum cover, which also

acts as a grease retainer. The yoke is made long enough to

provide for any necessary endwise slippage.

54. A type of universal joint that is widely used is known
as the block-and'irunnion type. One member of this joint con-
sists of a slott'^d jaw a, Fig. 30, that contains a square hole b

Digitized by

Google

§9

MECHANISM

in which the sqtiared end of the shaft fits. The second member
is a T head attached to the end of the other shaft. This head
consists of the roimded center piece c, carrying two arms upon
which the bronze or steel blocks d are free to turn. WTien
assembled, the blocks are inserted in the jaws of the member a

Fig. 30

where they are free to slide and permit the desired tmiversal
motion. This joint also acts as a slip joint, taking care of any
variation of distance occasioned by the jotmcing of the auto-
mobile on rough roads. The joint is enclosed in a pressed-steel
casing e that is fastened to the member a and that contains
plugs / through which grease can be injected for lubrication.
A helical spring is usually placed between the face of the center-

FiG. 31

piece c and the member a, in order to give a cushioning effect.
Generally, the head c is attached to the end of the propeller
shaft and the member a to the transmission shaft or differential
pinion shaft. A leather boot is usually fitted over the end of
the joint to serve as a protection from dust and to help contain
the lubricant.

Digitized by

Google

80 TRANSMISSION AND CONTROL § 9

55. A single universal joint of any type has the peoJiarity
of not transmitting motion through an angle with a uniform
speed. For instance, suppose that in Fig. 31 the shaft a repre-
sents the main-drive shaft from the transmission and the'
shaft fe, the shaft driving the rear axle, the two being connected
by the propeller shaft c, assimiing the change-speed gears to be
located at the forward end of the propeller shaft. The angle
through which the motion is transmitted is made large, in order
to show clearly the relative positions of the joints.

Considering only the universal joint coimecting the driving
shaft a and the propeller shaft c, if the shaft a rotates at a uni-
form speed, the shaSft c will not rotate imiformly, but its speed
will increase and then decrease four times during each revolu-
tion. This alternate increasing and decreasing of the driven
shaft is due to the alternate increasing and decreasing of the
radii through which the forks of the joint revolve. For instance,
in the position shown in Pig. 31, a point / is at a certain pier-
pendicular distance from the center line of the driving shaft a,
but this distance gradually increases as the shaft c turns through
the next quarter of a revolution. The linear velocity, there-
fore, of the point / also increases, provided that the speed of the
driving shaft a remains uniform. During the second quarter
of a revolution, the speed of the point / decreases until the point
reaches the position marked /', after which the speed again
increases for a quarter of a revolution. On the fourth quarter
of a revolution, the speed of the point / decreases imtil it
reaches the position shown in the illustration. The speed of
the shaft c varies with that of the point /, which is fixed with
reference to c; hence, the driven shaft c will not rotate uni-
formly if the driving shaft a moves at a uniform speed.

56. By the proper use of a tmiversal joint at each end of
the propeller shaft, however, the shaft b can be made to rotate
at the same speed as the shaft a diuing all parts of a revolu-
tion. In other words, the connection between the shafts b and c
can be made to counteract the variable speed of the shaft c
as produced by the connection between the shafts c and a.
In order. to do this, it is only necessary that the forks oh the

Digitized by

Google

§ 9 MECHANISM 81

shaft c shall lie in the same plane. This may be otherwise
expressed by saying that the shaft c must have such a form
that if it is removed with the attached forks from the crosses d
and e and placed on the floor, it will lie flat. It is also required
that the shafts a and b make equal angles with the intermedi-
ate, or propeller, shaft c. This, of course, is the case when the
shafts a and b are parallel, as shown in the illustration.

57. Magrneto-Sliaft Couplings. — ^The couplings used for
connecting up magnetos and other auxiliary apparatus are
usually made with a certain degree of flexibility, in order to
provide for defects in shaft alinement; hence, these are in reality
a form of imiversal joint. Several varieties of magneto-shaft
couplings are in use, the prime object in each case being to secure
silence in running com-
bined with flexibility.

Leather and rubber
are used in various ,
ways in order to secure |
the necessary require-
ments. A common
form uses a leather

disk as part of the ^g. 32

drive, and thus obtains the desired flexibility. In some coup-
lings, as, for instance, in that used in the Stevens-Duryea car
and shown in Fig. 32, a leather disk a is placed between the
two shaft flanges b and c, and each flange is coimected to the
leather at two points, as shown. The power is transmitted
through the leather disk itself, which therefore gives a slight
flexibility and takes care of any change of alinement that may
occur in the shafts. The magneto timing in this particular
case may be adjusted without taking the coupling apart by
loosening the nuts d and e and turning the flange c, in which
slots instead of holes are provided.

In the magneto coupling of the Velie car, a rubber disk is
carried between the shaft flanges, giving the coupling the
necessary silence and play. The drive is direct from one metal
disk to the other, the rubber disk taking no part in transmitting

Digitized by

Google

82 TRANSMISSION AND CONTROL § 9

the power. In some cases, a leather disk or washer is used in
the same way.

58. Another form of magneto-shaft coupling is that employ-
ing internal and external gears, such as is used on some Lozier
cars. This coupling is shown in Fig. 33. The teeth of the
internal gear a mesh with those of the gear h and the power is
transmitted by them. The internal gear a is attached to the
drive shaft and the gear h is secured to the magneto shaft.

Timing adjustment
of the magneto is
made by slipping the
gear h out and turn-
ing it until the mesh-
ing is changed a tooth
or more, as required.
The magneto coup-
FiG. 33 ling of the Willys-

Knight car is of the form shown in Fig. 33, but differs from that
of the Lozier in that the inner gear-wheel is made of leather.

In some couplings, a collar carrying two or more anns is
keyed to the magneto shaft. The arms of the collar engage
with slots in a fiber disk that is keyed to the driving shaft.

59. The Bosch magneto coupling, shown in Fig. 34, makes
use of a laminated stefel spring for securing the desired flexibility.
The driving member of this coupling consists of a body a,
view (a), that carries a flat laminated steel spring b made up
of a large nimiber of fine spring-steel plates, or leaves. The
driven member, which is presented in detail in view (6), is a
cone-shaped hub c that is bolted to a ring d having two fiber-
lined slots e diametrically opposite each other. When assem-
bled, as in view (a), the part c is attached to the armatuie shaft
of the magneto and the flange a is seciu-ed to the driving shaft,
the ends of the spring carried by a being engaged in the slots e
in the driven member. The drive is through the laminated
spring, which gives it the required flexibility. Adjustment
for timing the magneto is had by means of three taper-headed
bolts / that are held in place in the part d by means of a

Digitized by

Google

§9

MECHANISM

circular groove, into which the heads fit. The ring d can be
turned relative to the part c and hence to the magneto armature,
by loosening the nuts on the three bolts. The bolts may be
removed through a slot g in the ring d.

(bj

Pig. 34

A distinctive feature of the Bosch coupling is the graduated
scale shown at fe, by means of which the setting of the magneto
armature may be accurately regulated.

Fig. 35

60. The coupling illustrated in Fig. 35 is known as the
Oldham coupling and was formerly very popular as a magneto
connection. It is still used to a large extent, but is liable to
develop a knock if not closely engaged. It consists of three

Digitized by

Google

84 TRANSMISSION AND CONTROL § 9

members, shown separated in order to make the construction
clear. Both the driving member a and the driven member b
have a groove cut across the face of the flange, and the connect-
ing member c has a rectangular projection on each face, the two
projections being at right angles to each other. The pro-
jections fit loosely into the grooves of the driving and driven
members. The Oldham coupling can be employed only where
difference of alinement is very small.

DIFFE«RENTIAL OEARS

61. Differential gears are composed of a set of four or
more gears attached to the ends of two shafts that come together
and are usually in a straight line, so that both will rotate in the
same direction; but if either meets with extra resistance, it may

rotate more slowly than the
other or may stop altogether.
In automobiles, these gears
are used for transmitting
power to the two halves of the
rear-axle shaft in the case of
shaft-driven cars, or to the
countershaft in the case of
double-chain-driven cars.
Differential gears are of two
general types, depending on
the kind of gears used in their
constiuction, namely, the
bevel-gear differential and the
spur-gear differential.

^'^•^® 62. In Fig. 36 is shown a

spur-gear differential, the ends of the two shafts of which carry
the gears a and b. The flange ^ is a part of the case to which
the bevel driving gear for transmitting power to the differential
is fastened. The case carries a series of small gears d and e^
arranged in four pair, each gear being moimted on its own axle.
The two gears of each pair mesh together, and one is ia mesh
with the gear a while the other meshes with the gear 6. By

Digitized by

Google

§ 9 MECHANISM 85

this arrangement, both gears a and b are drawn in one direction,
and yet they may turn with respect to each other when the
resistance to the turning of one is greater than that of the other.
When the resistance to the movement of gears a and b is the
same, the four pair of small gears d and e do not turn on their
axles but simply carry the gears a and b around together.

63. In most cases the differential of an automobile is
driven from the propeller shaft by means of a bevel gear and
pinion. The worm-
gear drive is also
used successfully. A
third type of gearing,
which embodies a
combination of the
other two, is shown
in Fig. 37. This type
is known as the
worm-bevel drive and
the example shown is
that used on some
models of the Pack-
ard car. When as-
sembled in the car,

^- . . . - ' Pig. 37

the pmion a is keyed

to the drive shaft of the speed-change gears, which in this car
are located at the rear axle, and the large gear b is bolted to the
differentialncase. The gear-teeth are cut at an angle so that
one set of teeth is constantly meshing while the next set is
becoming disengaged, thus affording a continuous contact in
the same respect that it is accomplished with the worm-drive,
although not to the same extent. The chief advantage claimed
for the so-called worm-bevd drive is its quietness, which is due
to the fact that there is practically no backlash, or looseness,
between the teeth with this design. One set of teeth is con-
stantly meshing while the next is becoming disengaged, thus
affording a continuous contact similar to that accomplished
by the worm and worm-gear drive.

Digitized by

Google

TRANSMISSION AND CONTROL

§9

CONTROL MECHANISMS

STEERING MECHANISMS

ABBANOEBfENT OF STEEBINO CONNECTIONS

64. When a car is traveling straight ahead, the wheels
stand in the position shown by the full lines in Fig. 38, which
is a diagrammatic outline of a top view of the frame, axles,

and wheels of an
automobile. The
axles of the wheels
appear to be paral-
lel to each other
when ' looked at
from above, as in
this view. If the
car is to turn a
curve whose center
is at a, the front
wheels b and c must
be swiveled about
the more or less
vertical pivots d
and e of their re-
spective knuckle
joints. When turn-
ing toward the left,
as indicated in the figure, the left-hand front wheel b must swivel
through a greater angle than the right-hand front wheel, which
is at the outer side of the curve along which the car is travel-
ing. The path that the left-hand wheel follows is indicated by
the arc / g whose center is at a, and the path of the right-hand

Pig. 38

Digitized by

Google

§9

MECHANISM

wheel is along the arc h i, whose center is also at a. In order
that the front wheels may have a true rolling motion on the
grotmd, it is necessary for them to swivel to such an extent that
their axes, if extended, will intersect on an extension of the rear
axle, as shown. The lines ad and ae represent extensions of the
axes of the front wheels. The angle through which the left-hand
wheel must be swiveled is shown at /, and that through which
the right-hand wheel must be swiveled, at k. It can be readily
seen that the arc ; for the left-hand, or inside, wheel is larger
than the arc k for
the outside wheel c, \ \ /,^j

'^/

.4'/%

XV-

65. One of the

two methods of
connecting wheels
together to fulfil the
conditions just
mentioned is shown
in Fig. 39. The full
lines indicate the
position of the
steering mechanism
for the car to go
straight ahead.
The arms a and b
of the steering
knuckles are con-
nect^ by the dis-
tance rod c. These arms a and b stand in such a position
when the car is going straight ahead that if a line is drawn
throu^xi the center of the swivel pin d of one of the knuckle
joints and also through the center of the pin connecting that
arm to the distance rod, and another line is similarly drawn
through the swivel pin e and the pin connecting the correspond-
ing arm to the distance rod, these two lines will intersect each
other on br near the center line of the axis common to the rear
wheels, as indicated at/. The length of the distance-rod arms a
and b on the steering knuckles is made such that when the

222B— 38

Pig. 39

Digitized by

Google

TRANSMISSION AND CONTROL

§9

wheels are swtmg aroiind to ttim a curve, the wheels will take
positions in which their axes, if extended, would intersect on
or near an extension of the center line of the rear axle. The
intersection for this position is shown at g.

If the steering mechanism were mathematically correct
in its operation, then, for any position of the swiveled road
wheels, the intersection of the extended axes of the front
wheels would Ue exactly on the extension of the rear axle.
The mechanism shown, however, does not exactly give this
result, but one that is near enough for all practical purposes.

66. The second method of connecting the front wheels
together is by placing the distance rod in front of the front axle
with the arms of the knuckles extending forwards to engage
with it, as shown in Fig. 40. In this illustration, it is assumed
that the axle is viewed from the front. In this case, the distance
between the ends of the steering-knuckle arms is greater than
the distance between the steering-knuckle pins. The same
condition exists as to the lines through the steering-knuckle
pivots and connections of the distance rod intersecting at or
near the center of the rear axle.

flTTEEBINO OBABS

67. Classification. — Steering gears maybe broadlydivided
into tiller steering gears and wheel steering gears. In a tiller
steering gear, steering is effected by moving by hand a long

Digitized by

Google

§9 MECHANISM 89

lever, which in turn is cxmnected by suitable means to one of the
steering knuckles; this form of steering gear is now practically
obsolete, being used only on some light electric vehicles. In a
wheel steering^ gear, as implied by the name, steering is
effected by turning a wheel, ranging in modem cars between
16 and 20 inches in diameter.

Steering gears may also be classified as reversible and irreversi-
ble steering gears. When an obstruction striking one of the
road wheels will cause the hand steering wheel to rotate and
thus deflect the car from its direction of travel, imless the steer-
ing wheel is very firmly gripped by the hands of the driver,
the steering gear is called a reversible steering gear. It is
evident that the reason for the name is that it is possible to
rotate the hand wheel by force applied to one or both of the
road wheels. A steering gear that cannot readily be reversed
in this manner is called an Irreversible steering gear. While
none of the steering gears in actual use fully possess this prop-
erty of irreversibility when in good working order, they are
tisually referred to as being irreversible when but little effort at
the hand wheel is required to keep the car from being deflected
from its path when the road wheels strike an obstruction.

68. Various methods are employed for connecting the lower
end of the inclined shaft that carries the steering wheel to the
reach rod, in order to transmit the required motion to the steer-
ing knuckles. In every case, a turn of the wheel rotates a short
arm that in turn rotates the steering knuckles through the reach
rod. The steering mechanism at the bottom of the inclined
shaft usually consists of a worm and complete worm-wheel
or a worm and sector, although some form of screw-and-nut or
pinion-and-gear connection is also sometimes used. In one
car, the lower end of the shaft is connected directly to the reach
rod by a short crank-arm while a planetary gear-set is provided
at the top for transmitting the movement from the wheel to the
shaft.

69. Worm-and-Worm-Wlieel Steering Gear.— The
most popular type of steering gear is that emplo3nng a worm and
worm-wheel. The Gemmer steering gear, which is an example

Digitized by

Google

90 TRANSMISSION AND CONTROL § 9

of this tjrpe, is shown in Fig. 41. Part of the steering wheel and
column is cut away, exposing to view the interior arrangement.
Within the stationary housing a is the steering shaft, or mast, b,
carrying at its upper end the steering wheel c and at its lower end
the worm d. The worm is supported at its top and bottom by
two ball thrust bearings e, the mast being also provided near
the top with a spring bushing /, in order to prevent rattling.

/ \

Pig.

The thrust bearings can be adjusted by means of the adjusting
nut g that screws into the housing h. A second stationary
tube i is located inside of the mast b ; its function is to carry the
quadrant / at the top of the mast, or shaft. This tube contains
two other tubes, k and /, by means of which motion is trans-
mitted from the throttle and spark levers, m and n, to the arms
o and p, respectively. In this particular case an electric-horn

Digitized by

Google

§ 9 MECHANISM 91

push button q is located in the center of the steering wheel and
is wired to the horn through the inner tube / by means of the
wirer.

When the steering wheel is rotated, the mast b transmits the
motion to the worm d and this, being in mesh with the worm-
wheel s causes that wheel to turn. The shaft t, which carries
the short arm «, is integral with the worm-wheel 5 and, hence,
rotates with any motion of
the steering wheel and in
turn causes the steering
knuckles to be rotated by
the reach rod, which, how-
ever is not shown in the
illustration. The steering
mechanism is so con-
structed that a turn of
the steering wheel right-
handed swings the front
wheels to the right and
steers the car in that direc-
tion. A turn of the steer-
ing wheel to the left steers
the car to the left.

Adjustment of the steer-
ing gear for wear is made
by changing the position
of the aank-arm u in rela-
tion to the worm-wheel s;
when the worm-wheel has ^^^- ^

worn appreciably in one place, an imwom portion can be
broi^ght into mesh with the worm by turning the arm through
90° on the squared end of the worm-wheel shaft. This steering
gear is of the irreversible type.

70. Wonn-and-Sector Steering Gear. — In the worm-
and-sector steering gear, a worm on the lower end of the steer-
ing shaft, or mast, meshes with a sector of a worm-wheel instead
of with a complete wheel. An example of this type is that used

Digitized by

Google

92 TRANSMISSION AND CONTROL § 9

on the Cadillax: automobile, which is shown in Fig. 42 with the
two parts of the housing separated. The worm a is carried on
the lower end of the steering shaft 6, as in the worm-and-whed
type, but in this case it meshes with a sector c. The worm is
fitted with two thrust bearings, one of which is shown at d,
that are made adjustable in the direction of the stieering shaft b.
The sector shaft e is carried on two bearings, the caps of which
are shown at / and g, and is made adjustable by means of two
eccentric bearing bushings that can be turned to any position,
thus moving the sector closer to or further from the worm, as
desired. The eccentric bushings can be locked in any position
by means of teeth h cut in their periphery and a locking pin
that screws into the casing and meshes with the teeth. The
eccentric bushing is a common form of adjustment in this type
of steering mechanism. The arm i is the crank-arm by means
of which the reach rod is shifted; it is clamped to the squared
eiid of the shaft e, as shown. This is also a form of irreversible
steering gear.

71. A feature of one model of the Cadillac worm-and-sector
steering gear is that the steering wheel is hinged in front so that
it can be dropped downwards, thus facihtating entrance and
exit on the driver's side of the car. However, practically all
other steering gears are provided with a steering wheel that is
fixed permanently to the steering shaft and cannot be dropped.

72. Screw-and-Nut Type Steering Gear. — ^An irreversi-
ble steering gear of the screw-and-nut type, as used on the Fierce-
Arrow automobile, is shown in Fig. 43. View (a) is a vertical
section of the steering column and wheel and view (&) is a
sectional view through the plane xy. In this device, a multiple
threaded screw a, confined endwise by ball thrust bearings b
and c, is attached to the lower end of the steering shaft d and
actuates a nut e. The nut is provided with projections, or
trunnions, carrying blocks/ that rest in slots of a forked lever g.
The lever g is keyed and pinned to a spindle h that carries the
reach-rod crank-arm i. Rotation of the steering wheel / causes
the nut e to travel up or down, thus swinging the lever g and
actuating the crank-arm and reach rod through the spindle h.

Digitized by

Google

Fig. 43

Digitized byLjOOQiC

94 TRANSMISSION AND CONTROL § 9

The steering gear shown is an example of one with the shafts
for operating the throttle and spark advance located outside of
the steering column. The lever k operates the throttle by means
of the shaft / and arm m, and the lever n is connected to the
spark advance mechanism through the tube o and the arm p.
These levers and connections are carried on the outside of the
steering column by suitable brackets.

73. Fig. 44 shows the mechanism of the Jacox screw-and-
nut type steering gear, which makes use of a right-and-left
threaded screw and two half nuts instead of a single nut.

The screw a, which
is attached to the
lower end of the
shaft that carries
the steering wheel,
has two threads cut
over each other —
one right-handed
and one left-
handed. The half
nuts b and c sur-
round the screw,
one meshing with
the right-hand
thread and the
other with the left-
^'G- 44 hand thread so that

one slides up and the other slides down within the gear
housing d when the screw is rotated. To the lower end of
each of these half nuts is pinned a hardened-steel block e that
bears on a roller / at each end of a rocker g. The rocker is
mounted on a horizontal shaft h that also carries the reach-rod
crank-arm.

When the steering wheel is rotated so as to cause the half nut b
to travel upwards and the half nut c downwards, the bearing
block e under c presses downwards against its roller, and turns
the rocker g. Motion is thereby imparted to the shait h and to

Digitized by

Google

§9

MECHANISM

the reach nxi, by means of which the front wheels are swung
in the direction desired.

The bevel pinions at the lower c
connect the shafts belonging to tin
throttle and spark advance.

74 . Bevel-Pinion-and-Sect

Reo steering gear, shown in Fig. 4
pinion-and-sector type and belo
Because of the nature of its constr
mits a shock from the front road
much more readily than the gea

Fig. il

cars equipped with reversible stee
to have the steering knuckle pii
motion can be transmitted from t
mechanism. This may be accom]
knuckle pivot pin or the wheel sj
the pivot pin in line, or nearly in
wheel touches the groimd.

75. Referring to Fig. 45, a b ^ .^^

steering shaft b and meshes with a sector c of a bevel gear. The
sector is mounted on a short shaft d that also carries the reach-
rod arm e. A movement of the steering wheel rotates the

Digitized by

Google

96 TRANSMISSION AND CONTROL §9

pinion and this in turn rotates the sector and transmits the
motion to the crank-arm, which is connected to the steering
knuckle pins in the usual manner. The thrust of the bevel-gear
sector is taken by a roller / that is carried by a plimger g.
Adjustment of the sector is had by means of a screw h that is
used for adjusting the position of the plimger g. A spring i is
located within the screw and plimger, which are made hollow.
This spring always keeps the roller in contact with the sector.

76. Planetary Type of Steering G^eax. — In the planetary
ty*pe of steering gear, which is used on the model' T Ford car,

the gearing is located
at the top of the
steering column. The
inclined steering shaft
is connected directly
to the reach rod by a
crank-arm that is
keyed to its lower
end. However, the
steering wheel is not
fitted to the upper
end of this shaft as in
the gears previously
described, but is con-
nected to it through
a small planetary

Fig. 40 ^,

gear-set. The ar-
rangement of the gears of this set is shown diagrammatically
in Fig. 46. The internal gear a is stationary, being brazed to
the outside tube of the steering column. Meshing with this
gear are the three planetary gears b that are mounted on pins
carried by the head of the steering shaft. The small spur gear c
is integral with a short shaft that has a bearing in the steering
shaft and that carries the steering wheel. This gear meshes
with the three planetary gears b.

When the center gear c is turned by the steering wheel,
motion is imported to the planetary gears b and they are rolled

Digitized by

Google

§9 MECHANISM 97

around the stationary gear a in the same direction in which the
center gear is turned. The planetary gears b are thus carried
bodily aroimd and as their pins, or studs, are attached to the
upper end of the steering shaft, they turn that shaft with them.
A movement, therefore, of the steering wheel, turns the inclined
shaft and swings the reach-rod arm, imparting motion to the
steering knuckles in the usual manner.

The planetary steering gear is of the reversible type, as motion
can be imparted to the steering wheel by moving the front
wheels.

BRAKE MECHANISM

CONTBACTINO ANB JBXPANDINO BRAKES

77. The brakes used in automobile practice consist of a
cylindrical member, or brake drum, attached to some rotating
part, and a contracting or expanding member, or brake band,
supported by some fixed part of the car. The brake band is
applied by levers operated from a pedal or hand-brake lever.
If the band is of the contracting t3rpe and is applied to the
outside of the drum, the brakes are called contracting braises ;
if it is an expanding band and is applied to the inside of the drum,
they are called expanding brakes. It is the usual practice
to fit two entirely separate sets of brakes to automobiles. The
one brake system is used in ordinary service, and is therefore
called the service brake. The second brake system is intended
for emergency use, and hence the term emergency brake is
applied to it.

It was formerly the common practice to place the service
brake on some rotating part of the speed-changing mechanism,
or on a drum placed directly on the propeller shaft, and to
apply the emergency brakes to a drum fastened to each rear
wheel. The present tendency is to apply both sets of brakes
to drums bolted to the rear-wheel hubs, making the one set con-
tracting and the other expanding. Either the service brake
may be of the contracting type and the emergency brake of the
expanding type, or the opposite may be true. There is no fixed

Digitized by

Google

98 TRANSMISSION AND CONTROL §9

rule governing the type of . either set of brakes. In a few
cars, however, both sets of brakes are o( the exptoding type and
are located side by side within a single brake drum.

78. The most common form of hub brake consists of a con-
tracting brake, operated by means of a bell-crank, and an
expanding brake, operated by means of a cam. An example of
this form is found in some designs of the Timken-Dctroit rear
axles, and is shown in Fig. 47. In order to show the details of

Fig. 47

the operating mechanism the brake drum is omitted from the
illustration.

The contracting band a is lined with wire-woven asbestos
fabric. It is attached at one end to the short arm of a bell-
crank 6, and at the other end it connects through a short link c
to the fulcrum of the bell -crank. The long arm of the bell-
crank may be connected by rods and levers to either a pedal or
a hand lever, and the brake is then applied by exerting a puU
in the proper direction on this arm. When the brake pedal or

Digitized by

Google

§ 9 MECHANISM 99

lever is released, the elasticity of the steel band a draws it away
from the drum. In addition to this, a releasing spring d is pro-
vided. This spring seats on a stop e that is stationary, so that
when the brake is applied, the spring is compressed. When the
brake is released, the spring expands and helps to expand the
band a. On the side of the brake opposite the operating
mechanism, there is a support f that helps to carry the band by
means of a bracket g. Between the support and the outer part
of the bracket, there are two springs that tend to keep the
brakes from rubbing on the drums when not in use. The action
of these springs can be limited by means of an adjusting screw.
Two supports A, one located on top and the other on the bottom
of the band a, preserve the brakes in their correct alinement.

79. In the cam-operated expanding brake shown in Fig. 47,
the double cam i acts on bearing surfaces carried on the ends
of the asbestos-lined band /. The band ; is supported at fe in
the same manner that the band o is supported at/. Two stops /,
which are pins secured to the axle housing and passing through
slotted holes in the brackets m, hold the expanding band in side-
wise alinem^t. The spring n is the releasing spring and holds
the ends of the band in contact with the cam i. The supports/
and k are carried on an e;ctension of the axle housing.

80. Adjustment of the contracting brake is made by means
of the nut o. Fig. 47, on the end of the link c. This nut is pro-
vided with a notch p that fits over a corresponding projection on
the supporting bracket; hence, the least adjustment that can
be made is one-half of a turn of the nut. The adjusting nuts
at q are used for centering the band on the brake drum, the
nut o taking care of the actual adjustment.

The expanding brake is adjusted by lengthening or shortening
the brake rod by means of a suitable tumbuckle.

81» The Stevens-Duryea brake, shown in Fig. 48, is an
example of a hinged contractlnsr brake and a toggle expan-
ding brake. The contracting brake band a, which is shown in
detail in view (6), is in two parts hinged at b. This brake is
applied in much the same fashion as that shown in Fig. 47, that

Digitized by

Google

100

TRANSMISSION AND CONTROL

§9

is, by means of a bdl-
crank c. The releasing
spring is shown at d. An
adjustment e is provided
for adjusting the clear-
ance of the brake shoes a
from the drum, which is
not shown in this illus-
tration.

The expanding band /,
which is shown separately
in view (c), is operated by
a togglejoint consisting of
three members g, fe, and i.
A force applied to the
member g tends to bring
the members h andt in
line and thus to expand
the band / and force it
against the drum. The
toggle is operated through
the crank /, which is car-
ried on the extension k,
view (o), of the axle tube.
Two releasing springs /
are also anchored on the
flange k. The position of
the band/ is adjusted by
the nuts m and n.

The contracting band a
is supported at b and the
expanding band at o, both
being carried by the
flange k. In this brake,
the expanding member is
not faced, affording an
example of a metal-to-
metal brake.

Digitized by

Google

§9 MECHANISM 101

The contracting brake is adjusted for tightness by the winged
nut py and the expanding brake is adjusted by turning the small

tumbuckle i of the togglejoint.

82. Some hub brakes, both of the contracting and of the
expanding types, are operated by means of short double-armed
levers. The Premier brake, in which both of the bands are
operated in this manner, is shown in Fig. 49.

Each end of the external-brake band a is attached by pins b
and c to a short lever keyed at its center to the brake shaft c.

Fig. 49

This shaft is free to turn in a stationary bearing e that forms
part of tlio rear-axle housing. It will be seen that if the shaft d
is turned, as, by pushing the emergency-brake lever forwards,
so that the pin c will move upwards and the pin b downwards,
the brake band will be shortened and contracted on the drum.
The brake band o is confined sidewise by hooks/, and its clear-
ance from the drum is adjusted by the screw g.

The internal brake consists of two shoes h and i pivoted at ;
to the rear-axle housing. These shoes can be pressed outwards

Digitized by

Google

102 TRANSMISSION AND CONTROL §9

against the inside of the brake drum by pulling forwards on a
lever arm attached to the short shaft carrying the lever k, from
the ends of which extend the links / and w to the free ends of the
brake shoes. The heUcal springs n help to release the internal
shoes from the dnrni and to hold them in position.

Both of the brakes here shown are lined with asbestos fabric.
They are truly dotible acting, by which is meant that they work
equally as weU when backing the car as whe^ going ahead.
This is not true of brakes where the force exerted by the opera-
ting mechanism is
greater on one end of
the band than on the
other, as, for instance,
where one end of the
band is anchored to the
axle housing.

Adjustment of the
Premier brakes is made
by turning the brake
rods imder the floor-
boards of the car.
These rods are equipped
with right-and-left-
hand threads and
locknuts.

83. In Fig. 50 is
^^' ^ shown the Premier rear

wheel and brake drtun removed from the axle. When assem-
bled, the drum o is interposed between the linings of the band a
and the shoes h and i. Fig. 49. This is the form of drtun used
on all hub brakes; one siuface of the drum makes contact
with each brake.

84. A form of bell-crank operating mechanism that makes
possible a double-acting brake is shown in Fig. 51. The
characteristic feature of this brake is the use of the slotted links a
connecting one end of the brake band b with tl^e link c. The
mechanism is supported by a stationary bearing d that is part

Digitized by

Google

§ 9 MECHANISM 103

of the axle housing. The link c is free to pass through the pin e
so that a pull on the rod / draws the band b tightly about the
drum g. The brake is shown in its engaged position with the
drum moving in the direction indicated by the arrow, or right-
handed. The brake operates just as eflBciently with the drum
moving in the opposite direction, because either end of the band
is free to wrap itself aroimd the drum, or cling to it; hence, the
brake is truly double acting.

This brake is adjusted for tightness by means of the adjusting
nuts h and the locknut i. The brake shown is known as the
Raymond double-acting brake.

85. An example of a service brake applied to a dnun on the
main shaft of the transmission is foimd in the Mercer car,
and is shown in Fig. 52. The brake consists of two shoes a
and b that are lined with asbestos fabric and surrotmd a
drum c on the shaft d. The brake is located close up to the
transmission casing e and the actuating mechanism is supported

222B~39

Digitized by

Google

104 TRANSMISSION AND CONTROL § 9

by that casing. The shaft/ carries two screws, one right-handed
and the other left-handed, that turn inside of the nuts g. When
the shaft is rotated in the proper direction, the nuts move
toward each other and tighten the shoes by means of the lugs h
that impinge on the shoes. The releasing spring i aids in
separating the shoes when the brake is released.

In the Mercer car, this brake is operated by a pedal. The
advantage claimed for it is that the same braking force is always

applied to both rear
wheels. On some
transmission contract-
ing brakes, a bell-
crank is used as in
some hub brakes.

BRAKE EX^UALIZEBS

86. Unless some
means are provided
for keeping the tension
equal in the two rods
that connect to the
shoes of a pair of hub
brakes, one of the
shoes, when applying
the brakes, will bear
against its drum
harder than the other
if the adjustment is
not perfectly the same
for each brake. Such
adjustment is difficult to obtain, and even then it will not gen-
erally continue as the brakes wear in service. When one hub
brake grips harder than its mate, there is a tendency to slew
the car around toward the side whose brake has the weaker grip.
Various forms of brake equalizers are used to obtain
equal force of application for a pair of hub brakes. Probably
the simplest form of equalizer is a bar a. Fig. 53, extending
across the car, and having a connection at each end to one of

Digitized by

Google

to the brakes, and the crank-levers at the adjacent inner ends
of the divided shaft are connected to a short equalizer bar in
the same manner as just described when the bar extends
completely across the car.

Digitized by

Google

106 TRANSMISSION AND CONTROL § 9

An arrangement of this kind as used in some Overland cars, is
shown in Fig. 54. The middle of the short equalizer bar a is
joined to the service-brake rod that runs forwards to the opera-
ting pedal. The ends of the bar are joined to two separate
cranks b and c, one of which is also connected to one of the
service brakes by a rod d. The other crank c is carried by the
shaft e that extends across the car and carries at its outer end a
second crank /, which in turn is connected to the second serv-
ice brake by a tension rod g. Thus, the pressure on the service
brakes is equalized by the bar a. The emergency brakes are
not provided with an equalizer. These are operated through
the rods h and the cranks i, which are moimted on a tube ; . The
tube is rotated by a hand lever through one of the cranks and
the rod k. The springs / and m aid in releasing the brakes.

In other equalizers of this type the rod d is joined to a ^parate
crank that is connected by a short shaft to the equalizer crank b.

88. Even with a brake equalizer of the most effective form,
the resistance that a pair of hub brakes offers to the rotation
of the wheels is not the same, unless the coefficient of friction
between the rubbing surfaces of the brake shoe and drum
is the same in eafch case. Thus, if one brake is dry and the
other oily, they will not grip the wheels so as to resist the
rotation of each wheel with equal force, even though the pres-
sing of the shoe against the drum is the same for each brake.

Digitized by

Google

BEARINGS AND LUBRICATION

(PART 1)

BEARINGS

PLAIN BEARINGS

DEFINITIONS

1. The oldest and simplest form of bearing that is widely
iised in automobile practice, not only in the engine, but also in
parts of the running gear, is that known as a plain bectring.
Such a bearing consists essentially of two parts, namely, a
member, called the journal, having a surface that fits freely a
corresponding hole in another member, called the box. One
of these two members is stationary and the other is free to
revolve or to slide in the direction of its axis.

Plain bearings are of two general types: noftrodjustable
and adjustable. There are two classes of non-adjustable bear-
ings, namely, those having a bushed box, that is, a box fitted
with a removable solid bushing or liner, and those having no
bushing. In adjustable bearings, the box is divided into two
parts; such division is made for convenience in assembling the
bearing and taking it apart, and also for making adjustments
to take up wear and to secure a proper fit between the journal
and the box. A lining is very often used between the journal
and the main body of the box. The object of using the lining
is to provide a niore suitable material for the jotmial to rub
against than that which is used for the supporting parts or

COPTinCHTBD BY INTKHNATIONAL. TCXTBOOK COMPANY ALL HIOHTS NKSKIIVKO

§10

Digitized by

Google

BEARINGS AND LUBRICATION

§10

frame of the machine, or to provide a ready means of repla-
cing a worn part. This lining is made in two parts to suit the
two parts of the box; when the lining is made separate from the
box and is readily removable, its two parts are spoken of as
the bearing brasses. This term, however, does not necessarily
mean that the lining is made of brass.

Although, in most bearings used in automobile work, the
journal rotates in the box, as, for instance, in the crank-shaft
and cam-shaft bearings of the engine, there are others in which
the moving member slides back and forth in the box, as, for
instance, the valve stems and valve lifters of the engine and the
sliding gears of the transmission.

NON-AINrUfiTABLB PLAIX BEARINGS

2* The class of non-adjustable plain bearings in which no
bushings are used is confined in automobile work chiefly to
Joints on the brake connections, the transmission rods, the tie-
rod joining the steering knuckles, and in similar places where
there is very little movement and hence little wear.

The form that these bearings usually take in automobile
work in the places referred to is known as the yoke-andreye rod.

r«;

Pic. 1

of which the yoke is made either adjustable or plain. The
proportions of yoke-and-eye-rod bearings have been standard-
ized by the Society of Automobile Engineers, and their recom-
mendation is now largely followed by manufacturers.

3* Fig. 1 (a) shows a plain yoke end consisting of a fork a
and a circular stem 6. A hole c is drilled through each jaw of
the fork. The stem b is welded to the rod to which the yoke

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 3

end is to be applied, the yoke end being made from drop-
forged steel. The eye-rod end is shown in (b) ; it fits between
the jaws of the yoke end and has drilled through it a hole of
the same
rod end a
shown in
drilled tl
is passed
assembler
AnadJ
drical ste

yoke end,
out. Thi
and the 1
by screwi
In yob
to be the
ing; moti
joint pin.

4. A

which ill

of the Fo

steering knuckle b turns is stationary in the axle end, being

screwed into the lower jaw c and locked by a locknut d and a

Digitized by

Google

4 BEARINGS AND LUBRICATION § 10

cotter pin. The steering knuckle is fitted with two removable
bushings e, which are pressed into it, and on the inside of these
btishings is a close working fit on the spindle bolt. This bolt
in this case forms the journal of a bearing and is stationary;
the steering knuckle, with its two bushings, forms the box of
the bearing and is movable.

The object in bushing a plain non-adjustable bearing is to
permit an easy restoration of a proper working fit between the
journal and the box by substituting new bushings and perhaps
a new journal for the old and worn-out bushings and journal.

5. Bushed plain non-adjustable bearings have been used
on rear axles for the driving pinion shaft and also for the dri-
ving shafts; they have also been used for the end bearings of
crank-shafts, although their use for this purpose is now uncom-
mon. The cam-shafts and pump and
magneto shafts of engines very fre-
quently run in bushed boxes.

ADJUSTABLE PLAIN BEARINGS

6. A typical adjustable plain
bearing is shown in Fig. 3, which
illustrates the crankpin end of the
connecting-rod used in some North-
way motors. The connecting-rod is
made of drop-forged steel; its large
end is bored out cylindrical, the holes
for the bolts a are drilled, and the
fprging is then sawed apart. The box
^^' ^ is thus formed by the connecting-rod h

and the cap c, and is lined with removable bearing-metal
brasses** d that have a flange at each end to confine them
sidewise. Thin strips of sheet metal, called shims, are placed
between the connecting-rod part of the box and the cap, as
shown at e. In order that oil may be properly distributed all
over the bearing, oil grooves / are cut into the brasses, as
shown. These oil grooves communicate, in the upper brass,

Digitized by

Google

BEARINGS AND LUBRICATION

with the oil hole g, through which oil splashed up by the
(xwmecting-rod when in motion enters this brass; the oil
grooves in the cap communicate with the oil scoop A, which in
this particular case is a piece of copper tubing. The oil scoop,
as the crank nears the bottom dead center, dips intx> oil
contained in a trough beneath the crank and not only scoops
up oil that passes upwards to the oil grooves of the lower
brass d, but also splashes the oil aU over the inside of the crank-
case, thereby lubricating the pistons, wristpins, cam-shaft, and
main bearings.

In automobile-engine work, it is now the common practice
to lock positively all nuts on bolts that hold the two parts of
bearings together. In this instance, locking is done by slotting
the nuts i and passing a cotter pin / through the bolt and a pair
of opposite slots in the nut; the slotted nuts are spoken of as
castellated nuts. To prevent the bolts from turning while
screwing the nuts on or off, the head of each bolt, in this case,
is flattened on one side, and made to bear against a flat siuface
formed on the connecting-rod, as shown at k.

The two brasses of adjustable plain bearings are usually
relieved where they butt against the shims; that is, part of the
bearing surface is cut away, for instance as shown at /. Thus
there is formed a pocket that greatly assists in distributing
the oil evenly all over
the brasses and journal;
furthermore, as experi-
ence has shown, a bear-
ing having brasses thus
relieved is less liable to
be damaged by heating
due to friction than one
whose brasses are not
relieved.

■'l^»

1_| ;P F^PlJ-t

^v^^^

Pig. 4

7. In Fig. 4is shown,
partly in section, a com-
mon construction of a plain adjustable main bearing for an
automobile-engine crank-shaft. In order to show the bearing,

Digitized by

Google

6 BEARINGS AND LUBRICATION § 10

part of the walls of the upper crank-case a and the lower
crank-case b are broken away. The upper half c of the box,
following the most usual construction, is cast in one with the
upper crank-case; the lower half of the box, or the cap d, is
separate and is bolted on by a bolt at each side fitted with a
castellated nut that is secured by a cotter pin. Each half of
the box is fitted with a removable brass, or liner, the upper one
being shown in section at e\ in this particular case, each liner
is prevented from shifting by dowel-pins /.

The particular bearing here shown is the forward one of the
two middle bearings of the four-bearing crank-shaft of a six-
cylinder engine. It wiU be noticed that one side of each liner
has formed on it a flange g that bears against a flange h of the
crank-shaft. The second middle bearing has a similar flange
on its liners, but on the side opposite where the flange is located
on the bearing shown, and bearing against it is a crank-shaft
flange similar to h. The crank-shaft is thus confined longi-
tudinally. In practice, the distance between the flanges of the
brasses is made a little larger than the distance between the
flanges of the crank-shaft, thus permitting a little end motion
of the crank-shaft to and fro, which motion greatly assists the
oil distribution over the bearing and also tends to prevent it
from wearing in ridges.

A great many manufacturers of automobile engines make their
main bearing brasses with a flange on each side of the bearing,
and omit dowel-pins, which are then not needed.

Where splash lubrication is relied on for oiling the main
bearing, an oil pocket is usually formed on top of the upper half
of the box; some of the oil splashed up by the connecting-rods
finds its way into these pockets and is conducted to the liners
and journal by an oil hole. In the illustration, the pocket is
formed by two ribs i] the oil hole is shown at /.

When a main bearing is very long, as is always the case with
the rear main crank-shaft bearing, there may be as many as
three oil holes leading from the oil pocket to the inside. One
oil hole is then placed at the middle of the bearing, and the
other two are located about one-sixth the length of the bearing
from its ends.

Digitized by

Google

§ 10 BEARINGS AND LUBRIC

8. In some cases, one part of the main
of automobile engines is not cast integral
but is entirely separate therefrom and bolt<
tion placed crosswise and cast integral
An example of this kind of construction is
of the Rambler "Cross Coimtry'* car, i
Fig. 5, the box being entirely removed froi
shown separated. The box is in two
halves a and &, each of which has a rect-
angular opening to receive, respectively,
the upper brass c and the lower brass d.
When assembled over the crank-shaft
journal, the two halves of the box are
bolted to a cross-partition of the crank-
case. The two brasses are adjustable in
respect to the journal, each brass having
an inclined face, as c\ for instance,
against which bears one face of a wedge e,
the other face of the wedge having a
bearing in the box. Each wedge has two
studs; by turning the nuts / the brasses
can be brought closer together or slack-
ened. The method provided for the
adjustment of the boxes shown in Fig. 5
is very convenient, but it is very rarely
encountered in practice. In nearly all
cases where adjustable plain bearings
formed separate from the crank-case are e
is made by placing shims between the br
shims. The two halves of the box are
together, so that they virtually form a so]

SWIVEL BEARINGS

9. There are a ntmiber of places about
the yoke-and-eye-rod bearing, described i
used, because it permits of motion in onl
the bearing is required to permit motion h

Digitized by

Google

8 BEARINGS AND LUBRICATION § 10

a swivel bearing is used. The most prominent example of

parts requiring a swivel bearing is the reach rod nmning from

the steering-gear arm to the steering-knuckle arm; the first

arm swings in a vertical

plane and the second arm
in a plane that is practically
horizontal. Other examples
arefoimd in the control rods
joining the throttle lever to the carbureter throttle, and the
spark lever to the spark-advance-and-retard mechanism. In
some cases, swivel bearings are also fotmd on brake connections,
and quite frequently on radius rods for rear axles, and to a
slight extent, on front-axle radius rods. The case last men-
tioned is virtually confined to the model T Ford car, which
uses a cross-spring in front and hence needs radius rods for
the front axle.

10. The simplest form of swivel bearing is that shown in
Fig. 6, which bearing is used considerably in popular-priced cars,
on account of its low cost, for throttle and spark control rods.
The roimd control rod a is bent at right angles at each end, the
bent end b forming a journal that has a bearing in a hole drilled
in the end of the lever c, which may be the carbureter throttle
lever, a lever on the timer, the lever on the magneto breaker
box, etc. To permit a limited motion in all directions, the
hole in c is drilled somewhat larger than the end 6 and is counter-
sunk at both sides; that is, tapered, as shown. The joint is
prevented from coming apart by a cotter pin d passed through
the end 6. Sometimes a washer is
placed on both sides of the lever c
and around the journal 6. The form
of swivel bearing here illustrated is
non-adjustable for wear; conse-
quently, when wear occurs there
will be considerable lost motion ^^'^

between the throttle lever or spark lever and the carbureter
throttle lever or timer lever or magneto breaker-box lever that
cannot be taken up without using control rods larger in

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 9

diameter and reaming out the holes in the levers to which the
control rods connect.

11. A form of swivel bearing fqr carbureter and spark
control better than that shown in Fig. 6 is illustrated m Fig. 7.
It is known as a non-adjustable baU-and-socket ball joints and is
usually made of brass. The stud a is fastened to the carbureter
throttle lever or any similar lever, and carries a ball 6 on its
end. This ball is inserted into a socket c having a lug d that
is tapped out to receive the threaded control rod. The ball is
prevented from

coming out of the
socket by spinning,
or peening, the
metal arotmd the
mouth of the socket
down on the ball.
When this swivel
bearing has worn to

an objectionable W

extent, it is sup-
posed to bereplaced
with a new one.

12. An adjust-
able balUand-socket W
joint that is used ^°-®

for control rods, and also occasionally for steering-gear reach
rods, is shown in section, partly disassembled, in Fig. 8 (a).
The stud a, with its ball 6, is fitted to the end of the lever that
is to be moved by the control rod; the socket c is screwed to
the end of the control rod and locked with a locknut. The
ball is inserted through an opening d in the socket and has a
bearing against the spherical end e of the axial hole in the socket
and the spherical end of the adjusting screw /. The outer end
of the adjusting screw has three radial slots cut across it; a
cotter pin passed through the hole g in the socket and one of
the slots locks the adjusting screw, which can be turned by
one-sixth of a turn in adjusting the bearing.

Digitized by

Google

10 BEARINGS AND LUBRICATION § 10

13. In Fig. 8 (6) is shown a self-adjusting ball-and-socket
joint in which aU wear is taken up automatically. This form of
joint greatly resembles the one shown in (a) . It has a follower a
hollowed out to fit the ball, and a strong helical spring 6 is
placed between this follower and the adjusting screw c. The
spring always keeps the follower in contact with the ball and
the latter in contact with the spherical part of the socket. The
adjusting screw is kept locked by a cotter pin passed through a
hole in the socket and one of the slots in the outer end of the
screw. This form of ball-and-socket joint is largely used for

the steering-gear reach rod, there
being one at each end.

14. In some self-adjusting
ball-and-socket joints, there is a
follower on each side of the ball
and a strong helical spring behind
each follower. Such a joint is
g sometimes used on the steering-

knuckle steering arm, in which
case it acts as a shock absorber,
preventing road shocks from
being transmitted to the steering
gear.

In the smaller sizes, say for
J-inch control rods, self-adjusting
ball-and-socket joints are used
^®* ® for carbureter and spark advance

connections on most of the higher-priced cars. Ball-and-
socket joints as described in Arts. 12 and 13 are usually made
of steel and are generally case-hardened.

15. An adjustable ball-and-socket joint that is often
employed for hinging radius rods to the frame of the car is
shown in Fig. 9. The socket is made in two parts a and 6,
each of which has a hemispherical depression machined therein
to fit the ball c formed on the one end of the stud d, which is
fastened to the side member of the frame of the car. The two
halves of the socket are held together either by capscrews e or

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION ^^

by stud bolts and nuts. Adjustment is made either 1
shims between the two halves of the socket or by
joint g so as to let the two halves c»me closej" to. the I
part a of the socket is usually threaded, as shown at /",
the radius rod, which then can be adjusted for length
ing it into or out of the socket. When adjusted for h
radius rod and the socket are locked together by setti
nut tightly against the socket. In some cases the i
is not adjustable for length, but is brazed into the
of the socket; or, one part of the socket is forma
with the radius rod.

PLAIN THBUST BEARINOS

16. A bearing so constructed as to resist a thn
direction of the length of its journal is called a thrust
In its simplest form, it consists of a shoulder of i
fastened to the shaft butting against a correspondin|
of the box, although a hardened-steel washer or a fit
may be interposed between the two shoulders for th
of reducing friction and preventing the cutting of the
imder a great thrust. A bearing thus constructed i
plain thrust bearing, and in automobile work is usui
in steering knuckles. However, in the model T F(
plain thrust bearing is used at both sides of the c
housing inside the rear-axle tube, a fiber washer being :
between each side of the differential housing and a fla
axle housings, in which are placed the inner roller b
which the inner ends of the two halves of the axle sha
These bearings take the endwise thrust produced by
of the large bevel gear and pinion, and by the side p]
the wheels when turning comers.

In front axles, the weight of the car rests on th
knuckles, the thrust being in line with the steering sp
This thrust is resisted by the one end of the steering knuckle
butting against a jaw of the front axle, a washer of hardened
steel, and sometimes several washers, being interposed between
the two surfaces taking the thrust when a plain thrust bearing
is employed.

Digitized by

Google

12 BEARINGS AND LUBRICATION § 10

MATERIAIiS FOB PLAIN BEABINOS

17. In automobile work, the journal of bearings as a general
rule is of steel; often it is hardened and tempered, or heat-
treated, as it is called, and finished by grinding in a grinding
machine, which process makes the journal truly round, accu-
rately to size, and very smooth. The metals used in the box
are cast iron, hardened steel, phosphor-tronze, white brass.
Babbitt, and, for bearings on which the load is very light,
brass.

18. Cast iron, when copiously lubricated at aU times,
makes an excellent bearing material, especially when the
journal is of hardened steel. It is open to the objection, how-
ever, that if the oil film between the cast-iron box and the sted
journal is broken, owing to lack of sufficient lubrication, the
cast iron will seize on the journal and both the box and the
journal will be badly torn. For this reason, when cast iron is
used, it is employed only in relatively unimportant bearings,
where a plentiful supply of lubricant can be given; for instance,
it is used in the engine of the model T Ford car for the cam-shaft
boxes.

19. Hardened-steel boxes in the form of solid bushings
are generally used in conjimction with hardened-steel journals.
Both bushings and journals are usually groimd after hardening
to make them truly cylindrical. Boxes of this kind are some-
times foimd in very high-grade engines in the wristpin end of
the connecting-rods, and in high-grade front axles in the ends of
the jaws through which passes the hardened and ground spindle
bolt of the steering knuckles. When well lubricated, hardened-
steel boxes working in conjunction with hardened-steel jotimals
will wear exceedingly well under pressures that would simply
crush other kinds of boxes; even when indifferently lubricated,
the wear is very small. This renders their use advisable for
inaccessible places, and places in which lack of room demands
a non-adjustable plain bearing of very great durability. The
only reason against a more general adoption of hardened-steel
boxes in. places where they can be used is their high first cost.

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION

20. Phosphor-bronze, made according to tl
tions of the Society of Automobile Engineers, is a
taining approximately 80 per cent, of copper, 10
lead, 10 per cent, of tin, and a quantity of phosphorus
ing one-quarter of 1 per cent., nor less than five one
of 1 per cent. This bearing metal stands up very
heavy loads and lasts well even under scanty lubr
automobile engines, it is used considerably for bot
and wristpin bearings and in other places where il
contact with a hardened-steel journal. The use c
bronze boxes in connection with soft-steel journals is
owing to the rapid wear of the soft steel, even t
lubrication, when this combination of box and jour

21. White brass is an alloy that contains froi
cent, of copper, not less than 65 per cent, of tii
28 to 30 per cent, of zinc. This alloy is often us(
crank-shaft bearings and for connecting-rod crank-j
giving excellent results in conjimction with soft-st
when generously lubricated at all times.

22. Babbitt is a trade name that covers a la:
alloys made by melting together different proporl
copper, antimony, and lead. It is a very soft bei
has a low melting point, and can easily be fused in i
by an ordinary fire. Babbitt is relatively cheap
good antifriction metal, for which reason the bett
it are very extensively used in automobile engines fo
shaft and the crankpin end of the connecting-rods
pressiire on each bearing is relatively low. None of
metals are suitable for wristpin bearings, because ov
small size, the bearing pressure is very high.

For a high-grade Babbitt metal, the specificat
Society of Automobile Engineers demand 84 per <
9 per cent, of antimony, and 7 per cent, of copper

Die-cast Babbitt bearing brasses are now in ex
these brasses are cast in steel molds from which the
partly exhausted, or into which the molten met
under pressure. Such brasses are interchangeable i

222B-^0

Digitized by

Google

14 BEARINGS AND LUBRICATION § 10

so dose to the correct shape that they require no machine work
or hand fitting to the boxes ; hence, their replacement when badly
worn is an easy matter.

23. Brass is not used as a bearing metal in engines, trans-
nfiissions, axles, etc. ; when serving as a bearing metal, its use
is generally incidental to the part forming the box being made
of one of the many alloys containing copper, tin, zinc; and lead
that are usually spoken of as brass. Thus, the bearing boxes
for the carbureter throttle valve stem are usually of brass,
because the carbureter body is made of brass.

ANTIFRICTION BEARINGS

CXiASSIFICATION

24* In all plain bearings the bearing surfaces of the box and
the journal, when either is in motion, slide upon each other-
Experience has shown that the resistance to sliding, that is,
sliding friction, is very much greater than if rotating members
of a bearing can roll upon each other; in other words, rolling
friction is very much smaller than sliding friction tmder the same
conditions. Bearings constructed so as to have rolling friction
between the journal and the box are called antifriction bear-
ings. Such bearings are divided into two general classes, in
accordance with the means employed to substitute rolling fric-
tion for sliding friction, namely, roller bearings and ball bearings.

25* Roller bearings may be divided into straight roller
bearings and tapered roller bearings. Straight roller bearings
may be subdivided into flexible roller bearings and solid roller
bearings, according to whether the rollers are flexible in construc-
tion or solid. In both types, the rollers are cylindrical, or
straight, in machine-shop parlance. Flexible, and also solid
straight, roller bearings are generally adapted for radial loads
only, that is, loads acting at right angles to the center line, or
axis, of the journal; by forming the rollers with a shoulder they
can be made to carry axial, or thrust, loads, that is, loads acting

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 15

in the direction of the axis of the journal. Straight roller
thrust bearings, while in existence, are not used in automobile
work. Tapered roller bearings have rollers that are frustums
of cones and are so moimted upon hardened and groufid steel
bushings, called races, that the center lines of all the rollers lie
on the surface of a right cone whose axis coincides with the axis
of the journal; when this condition is fulfilled, the rollers will
h^ve a true rolling motion. A tapered roller bearing can carry
both radial and axial loads.

26. Ball bearings used in automobile work can be divided
into three general classes, namely, radial ball bearings, radial-
and'thrust ball bearings, and axial, or thrust, ball bearings.
Radial ball bearings, as implied by the name, are intended for
radial loads, which means loads at right angles to the shaft,
although they can generally resist a slight thrust load. Radial-
and-thrust ball bearings can take radial and thrust loads with
equal facility; they differ from combination radial-and-thnist
bearings in that the two kinds of load are borne by a single
bearing. Ball thrust bearings are intended entirely for axial
loads, that is, thrusts in the direction of the center line of the
shaft.

All ball bearings consist of at least three elements, which are
the inner race, the balls, and the outer race. The inner race is
attached to the shaft and forms the journal; the outer race
is attached to the bearing housing and serves as the box; and
the balls provide for rolling friction.

27# Antifriction bearings are used in automobile work for
the front wheels, the rear axle and the transmission, as well as
for dynamo armatures, electric starting motor armatures,
magneto armatures, fans, etc., and in a very few cases they are
employed for main bearings of crank-shafts.

STRAIGHT ROLLER BEARINGS

28. Flexible roller bearings are made in two styles, which
are known as the standard Hyatt roller bearing and the high-
duty Hyatt roller bearing. Both types of bearing embody

Digitized by

Google

16 BEARINGS AND LUBRICATION § 10

the principle of a flexible roller, but the first type named is
intended for light radial loads, while the second type is used
for heavy radial loads.

29. A standard Hyatt roller bearing is shown disassembled
in Fig. 10. The rollers a are wound helically from flat steel and
are ground cylindrical after hardening. They are set in a cage b
made of two washers properly spaced by ribs c, to which the
washers are securely riveted. Projections d on each washer
enter the ends of the rollers and thus prevent them from falling
out of the cage. The rollers are sometimes run directly on the
journal and the box of the bearing; in better \;work, both the

Pig. 10

journal and the box are protected by removable liners. A liner
for the journal is shown at e, and a liner for the box at /. These
liners are formed from soft-sheet steel, and since they are split
as shown, they are easily forced into place or removed when
worn enough to need replacement. The outer liner should be
held from turning in the box by making the conical projection g
enter a hole drilled for this purpose into the box. A liner for
the journal is often omitted; when the metal of the journal
is very soft, however, a case-hardened steel liner is necessary.
This liner may have the form shown in e or it may be in the form
of a solid bushing that is pressed on the journal. Likewise,
the outer liner may be in the form of a solid bushing.

Digitized by

Google

Tr^\ T^T/^XT

§ 10 BEARINGS AND LUBR?

30* The high-duty Hyatt roller bee
standard bearing in that another brand
rollers, making them siiitable for higher
a somewhat diflEerent form of cage is use
It also differs from the standard bearir
any are used, are ntiade in the form o
that have been carefully groimd inside ai
ing. Liners are used only when the jc
of soft material. When the box is of h
liner is used, and* when the journal is of
liner is employed. The liners are ofte
outer rdces.

The cage of this high-duty bearing is
properly spaced by distance rods 6,
there being a distance rod between
each pair of rollers, so that they can
never come in contact with each other.
In the standard bearing cage, as refer-
ence to Fig. 10 will show, there are two
rollers between each pair of distance
ribs, at c\ consequently, the two rollers
of each nest will be in contact when
the journal is rotating.

When either an inner or an outer
race, or both, are used, the race or ra
held from rotating on their seats either 1
into place or by locking them in some o

31. The object in putting the roller
bearing is to prevent them from twistinj
can be in contact with the journal or tt
whole length only when the center line
same plane with the center line of the t

32. In Pig. 12 is shown a Norma

a series of cylindrical rollers a run between a cylindrical inner
race h and a slightly curved outer race c. This curved bearing
tace of the outer race permits this form of bearing to undergo
slight errors of alinement without undue stresses on the rollers

Digitized by

Google

18 BEARINGS AND LUBRICATION § 10

or races; such errors may result from faulty moimting of the
races or from bending the shaft on which the inner race is
mounted. The rollers are caged between two rings d and e
and are mounted on pivot pins / fastened to these two rings.
A locking ring g locks the cage together, it being slotted, as
shown at g', to pass over a groove /' turned in each pivot pin.
The rollers and races are of hardened and groimd steel.

The Norma bearing differs from the Hyatt bearing chiefly
in that the rollers are in the form of soUd bushings.

33. Neither the Hyatt nor the Norma roller bearing, nor
any other bearing of this type, is suitable for any other than a

Fig. 12

radial load. When an axial or a thrust load comes on such a
bearing, this load must be taken by a separate thrust bearing
of either the plain or the antifriction type. By using a special
form of roller, however, in conjunction with a special form of
race, a cylindrical roller bearing can be made to carry an axial
load in one direction. The Bower roller bearing, which is shown
in Fig. 13, is a bearing capable of carrying both radial and axial
loads.

In view (a) one of the rollers of the Bower bearing is sho\\Ti
in perspective. It consists of a cylindrical part a that carries
the radial load, an enlarged part 6 in the form of two frustimis
of cones, and two pivots c that pass through holes in the side

Digitized by

Google

§ 10 BEARIN

rings of the cage wher
fine each roller.

A section through
outer race a has an (
shoulder 6; the inner i
der d. A thrust load

iaj

(d)

by the shoulders 6 an
conical surfaces of the
In view (c), the out
view (d) the inner race
assembled. The cag€
spaced and held toget
plete assembled bearii

Digitized by

Google

20 BEARINGS AND LUBRICATION § 10

Like all other cylindrical roller bearings, the Bower bearing
is non-adjustable radially, excellence of material and work-
manship being relied on to prevent
undue wear and subsequent looseness.
Replacement of worn parts is easily
effected.

34. The Standard roller bearing,

shown in perspective and partly in

section in Fig. 14, employs cylindrical

rollers a with conical ends. The

outer race is formed with a conical

shoulder 6, and the inner race has a

conical shoulder c. The radial load is

^°' ^* carried by the cylindrical part of the

rollers and races, and an axial load in the direction of the

arrow d is carried by the shoulders 6 and c and the conical ends

of the rollers. The rollers are confined by being set in pockets

formed in the cage e, which is composed of rings held together

by rivets /.

TAPERED ROLLER BEARINGS

36. A tapered roller bearing, as implied by the name,
employs tapered rollers, that is, rollers that are frustums of
cones, nmning in contact with tapered inner and outer races.
The most widely used bearing of this form, in automobile work,
is the Timken roller bearing, which is shown in Fig. 15. In (a)
is shown a section through the inner and outer race with a
roller a between the conical (tapered) surfaces of the inner
race 6 and the outer race c. The inner race is cylindrical on its
inside, and the outer race on its outside. The inner race has
two ribs with conical sides, the rib d entering a corresponding
groove e in the small end of the roller a. The conical face of the
rib / bears against the conical large end of the roller, as shown.
The ribs d and /, in conjimction with a cage in which the rollers
are set, hold the rollers in proper alinement with the races. The
cage is shown separately at (6) ; it is pressed in one piece from
sheet steel into the form shown. The inner race is shown in

Digitized by

Google

§ 10 BEARINGS AND

perspective in view (c), and aj
rollers, in (d). When thus assem

(a)

(e)

G. 1

rollers cannot separate. The outer race is shown separately
in (e), and the whole bearing assembled in (/).

Digitized by

Google

22 BEARINGS AND LUBRICATION § 10

The outer and inner races have their bearing surfaces formed
as frustums of cones whose apexes coincide and lie on the center
line of the journal; the center lines of the rollers lie on the siu*-
f ace of a cone whose apex coincides with that of the inner and
outer races, and consequently the rollers have a true rolling
motion. As in cylindrical roller bearings, the cage for the
rollers prevents their sidewise displacement.

A tapered roller bearing carries radial and axial loads, and
any radial looseness due to wear is readily taken up by forcing
the inner race farther into the outer race. This form of bear-
ing is always motmted so as to permit this operation to be

(a) (b) (c) (d)

Fig. 16

easily done. The races and rollers are made of hardened steel
and are very accurately grotmd after hardening. Tapered roller
bearings are largely used in the construction of rear axles.

36. The improved G^ran/ roUer hearing, made by the Stand-
ard Roller Bearing Company, is shown in Fig. 16. The tapered
rollers a, as shown in the sectional view (a), are not grooved
and their conical large end bears against a conical shoulder 6
of the inner race. The outer race is tapered inside and cylin-
drical outside. The rollers are set in pockets formed in a
two-part steel cage, the two parts of which are held in place by
stayrods, after the rollers have been assembled into the cage,
as shown in view (6). A perspective view of the inner race is
shown in (c), and of the outer race in (d). This roller bearing
consists of three separate structures, namely, the inner race,
the outer race, and the cage with its rollers.

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 23

RADIAL BALL BEARINGS

37. Radial ball bearings are divided into two general
types: the fuU ball bearing and the silent ball bearing. Each
type may have a single row of balls, when it is 'called a single-
row ball bearing, or it may have several rows of balls, when it
is called a multiple row-ball bearing. In present automobile
work, a radial ball bearing with more than two rows of balls is
hardly ever fottnd. Radial ball bearings are often spoken of
as annular ball bearings, there being an annular space between
the inner and the outer race, which space contains the balls.

38. A full-type annular ball bearing with a single row of
balls, as made by the Standard Roller Bearing Company, is
shown in Fig. 17 (a), in which

illustration part of the outer

race a is cut away in order

to show the assembly. The

outer race a and the inner

race b are grooved to a larger

radius than that of the balls c

in order that the balls may be

in contact with each race at a (a) (b)

single point in the same plane ^°- ^^

as the centers of the balls. The balls are introduced between

the races through a slot in the outer race, which slot cannot be

seen in view (a), but is indicated at d in the cross-section

shown in (6).

39. In all full-t)rpe annular ball bearings, which derive
their name from the fact that the annular space between the
two races is filled with balls, some means must be provided for
getting the balls into place. In some bearings of this type the
outer race is slotted and the slot left open; in others the slot
is closed by a filling piece; and in yet another form the balls
are introduced through a radial hole in the outer race, which
hole is afterwards closed by a hardened-steel plug that is
prevented from coming out by the housing into which the
outer race is forced. In still another form of annular bearing

Digitized by

Google

24 BEARINGS AND LUBRICATION § 10

of the full type, the outer race is made cylindrical, only the
inner race being grooved; consequently, the outer race can be
slipped in place after all the balls are placed in the groove of
the inner race. This form of bearing, which was used at one
time in the engines and also in the rear axles of White cars, is

(b)

(d)

Fig. 18

not a self-contained imit; that is, the inner and outer races and
balls will easily come apart when either race is removed from
its seat.

40. Annular ball bearings of the silent type have their
balls set in cages, so that they cannot come in contact with
each other. They derive their name from the absence of the
clicking sound, caused by the balls striking against each other,

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 25

that is found in ball bearings of the full type. Silent-type
annular bearings are made by many different firms, the various
makes differing from each other chiefly in the form of cage that
is employed.

41. Fig. 18 illustrates the silent annular bearing made by
the Hess-Bright Company and known as the H B—D W F
bearing. In view (a) is shown the bearing before it is assembled,
and in (6), the completely assembled bearing. View (c) shows
the cage that confines the balls. The same parts are lettered
alike in these views. The bearing is of the single-row type.
The inner race a is cylindrical inside and is grooved outside to
a radius equal to the ball diameter, as is also the outer race b.
The balls c are set in pockets d of the cage e. This bearing is

(a) (b)

Pic. 19

distinguished from many other silent types of ball bearings in
that the balls can be and are introduced between the Vaces
without either one of them having a filler slot; that is, the
grooves of the races are continuous. The pockets in the cage e
consist of U-shaped sheet-brass stampings, the legs / of which
are substantially straight and parallel before assembly of the
bearing.

To assemble the bearing, the inner race is inserted eccentric-
ally in the outer race and the proper number of balls are dropped
between the races, as is indicated in (d). The balls are then
spaced equidistantly, and the cage is put in place so that a
ball sits in each pocket. The free ends of the legs / are then
bent over the balls, which operation assembles the bearing
into a tuiit of which the component parts cannot come apart.

Digitized by

Google

26 BEARINGS AND LUBRICATION § 10

42. Whether or not an annular silent type ball bearing
that forms a unit when assembled must have filler slots cut in
the races is determined solely by the ntmiber of balls the man-
ufacturer has decided to use between the races. When a large
nmnber of balls are used, the bearing must have filler slots in
its races; sometimes the outer race has a filler slot, sometimes
the inner race has such a slot, and sometimes both races have
these slots. An example of the latter type is the New Departure
single-row annular ball bearing, which is shown assembled in
Fig. 19 (a) and disassembled in (6). In the illustration the
filler slot for the outer race is shown at a and the filler slot for

(a) (b)

Fig. 20

the inner race at b. The ball cage, or separator, c containing
the balls is made in two halves and of sheet steel; the two
hajves are riveted together after the bearing has been assembled.

43. It is possible to design an annular ball bearing in such
a manner that it can be entirely filled with balls or be made of
the silent type, just as is desired, without having filler slots in
either race; such a bearing, however, will not be a unit when
assembled. A well-known example of this form of bearing is
the S K F double-row self -alining ball bearing shown in section
in Fig. 20 (a) and partly assembled in (6). In both views, the
same parts are lettered alike. The inner race a has two grooves

Digitized by

Google

§10

BEARINGS AND LUBRICATION

side by side and so spaced that the balls b of the two rows lie
staggered in the pockets of the cage c. This feature can be
clearly seen in view (6). A curvature having a radius e f

Fig. 21

struck from the center e of the bearing is given to the outer
race d, and as a consequence the inner race, which is rigidly
mounted on the shaft to which it is applied, can rock slightly
in reference to the outer race under any springing of the shaft

Digitized by

Google

28 BEARINGS AND LUBRICATION § 10

without cramping the balls in any way. The cage c is formed
from sheet steel. View (6) indicates how the bearing is assem-
bled and shows that the outer race is free from the balls and
the inner race when the bearing is not attached to a shaft
and housing.

44. In some radial ball bearings, as, for instance, in those
made by Fiditel and Sachs, and known as the F. & 5. hall
bearings, self-alinement is secured by making the outer surface
of the outer race part of a sphere and seating it in a spherical
seat.

45. Various forms of ball cages are used for silent annular
bearings by different makers. Some of these cages have
already been shown in connection with several bearings illus-
trated and described; several other cages are shown in Fig. 21.
In order to illustrate these cages clearly, they are all shown
assembled with the balls in place but removed from the two
races; it must be distinctly understood that in the actual bear-
ing the cages are assembled after the balls have been placed
into the races.

Three different forms of cages used in the F. & S. annular
bearings are illustrated in views (a), (6), and (c). The one
shown at (a) is known as a ribbon cage or a ribbon separator , the
term ball separator being sometimes used instead of the term
ball cage. This ribbon cage is stamped from sheet steel and is
stiffened by ribs. The sheet metal cage at (6) is made from
two like rings pressed into shape and imited by rivets a when
the bearing is assembled. The so-called solid cage at (c) is
machined from soHd metal in two halves, with pockets to
receive the balls, which also are machined out of the soUd; the
two halves are fastened together rigidly when assembling the
bearing. The ball cage used in the R. I, V, annular bearings
is shown in (d). It greatly resembles the cage shown in (c),
and is also machined from the solid in two halves that are
riveted together when the bearing is assembled. The cage
shown in (e), which also is made in two halves pressed from
sheet metal and riveted together when assembling the bearing,
is used in the annular ball bearings made by the Standard

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 29

Roller Bearing Company. This cage diflEers from the one
shown in view (6) only in that it cxMitains fewer balls, com-
paring bearings of the same dimensions of the two makes,
because the bearing in which it is used has no filler slots in
either race.

46. Although annular ball bearings are designed primarily
to carry a radial load, they can safely carry an axial load equal
to about one-tenth the safe radial load. When the axial load
becomes greater than is safe, this load is taken by a separate
thrust bearing, which may be combined into a single tmit with
the radial bearing, but more frequently is entirely separate.

47. The annular type of ball bearings was developed in
Europe, where the metric system of measurements is in com-
mon use, and hence was made in sizes measured in nMlKmeters.
When the manufacture of these bearings was taken up in the
United States, the American makers adopted these same
measurements in order that their bearings would interchange
with the imported bearings, which accounts for the fact that to
this day the dimensions of annular ball bearings are expressed
in millimeters instead of inches.

The manufacture of single-row annular ball bearings is
standardized to a large degree, so that bearings made by differ-
ent manufacturers, but having the same trade number, will
interchange perfectly. The single-row annular bearings in
most common use are made in five series, in both the full and
silent types. These wires are as follows:

1. Medium and Heavy Series, Narrow Type. — ^Bearings of
this series are designated by numbers that identify them, and
are below 100.

2. Light Series, Narrow Type, — ^The identification numbers
begin with 100 and are below 200.

3. Light Series, Wide Type, — ^The identification niunbers
begin with 200 and are below 300.

4. Medium Series, Wide Type, — ^The identification numbers
begin with 300 and are below 400.

5. Heavy Series, Wide Type, — ^The identification niunbers
begin with 400 and are below 500.

222B-^l

Digitized by

Google

BEARINGS AND LUBRICATION

§10

The identification niimber is usually stamped on one of the
races, and sometimes on both, and even on the ball cage.
When this number is known, the series is also known; thus, if

TABLE I

BINOLE-ROW ANNULAR BALL BEARINGS, MEDIUM AND

HEAVY SERIES, NARROW TYPE

No. of

Inside Diameter

Outside Diameter

Width

Bear-
ing

Inches

Milli-
meters

Inches

MUli-
meters

Inches

Milli-
meters

.4724

1-4567

-3543

•5905

1-5748

•3543

.7874

2.0472

•3937

■9843

2.4409

•4724

1.1811

2.8346

.5118

1-3780

3-1496

•5512

15748

3-5433

.6299

1-7717

39370

100

•6693

1.9685 ,

4-3307

.7480

2-1653

4.6063

117

.7480

2.3622

5.0000

127

•7874

2-5591

5-3937

137

.8661

»3

2-7559

5-7874

147

•9449

2.9528

6.1811

159

•9843

3-1496

6.6141

168

1.0630

-7874

2-559»

•5512

.8661

2.8346

.6299

•9843

3-H96

.6693

1.0630

3-4645

.7480

1.1811

37402

•7874

1-3780

4-0551

103

.8661

an annular ball bearing is stamped 308, it belongs to the mediiun
series, wide type.

The identification niunbers and sizes of the most common
single-row annular ball bearings are given in Tables I to V, the
sizes being given in both millimeters and inches.

Digitized by

Google

BEARINGS AND LUBRICATION

48. Although the practice of designating annular single-
row ball bearings by the numbers here given is commonly
followed, there are exceptions. Thus, the New Departure

TABLE n

SINOLE-BOW ANNULAR BAIi BEABIN08,
NARBOW TYPE

UOHT SERIES,

No. of

Inside Diameter

Outside Diameter

Width

Bear-
ing

Inches

MUli-
meters

Inches

Milli-
meters

Inches

MiUi-
meters

I02

•3937

1.2598

.3543

103

•5905

1-4567

-3543

104

.7874

1-6535

-3543

105

•9843

2.0472

•3543

106

1.1811

2.4409

•3937

107

1.3780

2-7559

•3937

108

1-5748

3-1496

•4331

109

1.7717

33465

•4331

1 10

1.9685

3-5433

•4331

III

2.1653

39370

100

•4724

112

2.3622

4-1339

105

•4724

2-5591

45275

•5512

114

2-7559

4-7245

120

•5512

2.9528

5.1182

130

.6299

116

3-1496

5-3149

135

.6299

117

3-3465

57086

145

.7087

118

3-5433

5-9056

150

.7087

119

3-7402

6.2992

160

-7874

120

3-9370

100

6.4960

165

•7874

121

4-1339

105

7.0867

180

.8661

122

4-3307

110

7-2834

185

.8661

bearings of this type have the figure 1 prefixed to the trade
numbers given in Tables I to V. For instance, the New
Departiure bearing having the number 1404 has an inside
diameter of 20 millimeters, an outside diameter of 72 milli-

S 7. ;i "A

Digitized by

Google

BEARINGS AND LUBRICATION

§10

meters, and a width of 19 millimeters, which are the same
dimensions as those of bearing No. 404 in Table V. No con-
fusion arises in practice from these differences of nimibering
when a bearing is to be replaced by one of the same number

TABLE in

8INOI£>BOW ANNVLAB

BAIX BEABIM08,
WIDE TTTPB

UOHT 8EBIE8,

No. of

Inside Diameter

Outside Diameter

Width

Bear-
ing

Inches

MiUi-
meters

Inches

Milli-
meters

Inches

MilU-
meters

204

.7874

1.8504

-55"

205

•9843

2.0472

•5905

»5

206

1.1811

2.4409

.6299

207

1.3780

2.8346

.6693

»7

208

1-5748

3.1496

-7087

209

1.7717

33465

85-

.7480

210

1.9685

3-5433

•7874

211

2.1653

3-9370

100

.8268

212

2.3622

43307

.8661

213

2.5591

4.7244

120

•9055

214

2.7559

4-9213

125

•9449

215

2.9528

5.1181

130

-9843

216

3.1496

5-5"8

140

1.0236

217

3.3465

5-9055

150

1. 1024

218

3.5433

6.2992

160

1.1811

219

3.7402

6.6929

170

1.2598

220

3.9370

100

7.0866

180

1-3386

221

4-1339

105

7-4803

190

1-4173

222

43307

7-8740

200

1.4961

and of the same make; when it is to be replaced by one of a
different make, either the maker or his catalog is consulted for
the trade order number.

It must not be inferred that only the bearings given in Tables
I to V are manufactured; smaller or larger bearings can be

Digitized by

Google

§10

BEARINGS AND LUBRICATION

obtained in the five series, either on regular or special order,
and special sizes to suit special conditions are also manufactured.

TABLE rV

8INOLB-BOW AimUIiAR

BAU. BBABINGS,
WIDB TTFB

BIBDICU SERIES,

No. of

Inside Diameter

Outside Diameter

Widtli

Bear-
ing

Inches

MiUi-
meters

Inches

MiUi-
meters

Inches

MiUi-
meters

300

•3937

1.3780

•4331

301

.4724

1-4567

•4724

302

.5906

1-6535

.5118

303

.6693

1.8504

•5512

304

•7874

2.0472

•5905

305

•9843

2.4409

.^93

306

1.1811

2.8346

.7480

307

1.3780

3-1496

.8268

308

1-5748

3-5433

•9055

309

I.7717

3-9370

100

-9843

310

1.9685

4-3307

110

1.0630

2.1653

4-7244

120

1.1417

312

2.3622

5-1181

130

1.2205'

313

2.5591

5-5"8

140

1.2992

314

2.7559

5-9055

150

1.3780

315

2.9528

6.29912

160

1-4567

316

3.1496'

6.6929

170

1-5354

317

3.3465

7.0867

180

1.6142

318

3-5433

7.4803

190

1.6929

319

3-7402

7.8741

200

1.7717

320

3-9370

100

8.4646

215

1-8504

321

4-1339

105

8.8583

225

1.9291

322

4-3307

110

9.4488

240

1.9685

Neither does each manufacturer necessarily make all five
series of anntilar single-row ball bearings.

Digitized by

Google

BEARINGS AND LUBRICATION

In a very few instances, automobile manufacturers have
made their own annular bearings to their own standards; such
bearings, for replacement purpose, must as a general rule be
obtained from the proper automobile manufacturer.

49. All annular ball bearings are non-adjustable; they are
properly assembled at the factory and are intended to be

TABLE V

SINGLE-ROW ANNULAB BALL BEARINGS, HEAVY SERIES,
WIDE TYPE

No. of

Inside Diameter

Outside Diameter

Width

Bear-
ing

Inches

MilH-
meters

Inches

MiUi-
meters

Inches

Milli-
meters

403

.6693

2.4409

.6693

404

.7874

2.8346

.7480

405

.9843

3.1496

.8268

406

i.iSii

3.5433

•9055

407

1.3780

3.9370

100

■9843

408

1.5748

43307

IIO

1.0630

409

1.7717

47245

120

1.1417

410

1.9685

5.1181

130

1.2205

411

2.1653

5.5119

140

1.2992

412

2.3622

59055

150

1.3780

413

2.5591

6.2992

160

14567

414

2.7559

7.0867

180

^r-6535

416

31496

7.8740

200

1.8898

418

3.5433

8.8583

225

2.1260

420

3.9370

100

10.4331

265

2.3622

replaced with new ones when worn to an objectionable degree.
In many cases, worn annular ball bearings can be repaired,
however, at small cost, either at the factory where they were
made or at establishments specializing on this class of repair
work. The repair is effected by regrinding both races and

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 35

substituting larger balls; owing to the special machinery and
the high degree of workmanship required, this work cannot
be done in garages or ordinary machine shops, but must be
done by specialists.

The great success that has been obtained with annular bear-
ings is in a large degree to be attributed to their non-adjust-
ability, which feature prevents their overloading by a wrong
adjustment.

BADIAIi-AND-THBUST BALL BEARINGS

50. The earliest form of ball bearing staitable for combined
radial and thrust loads was developed in the early days of the
bicycle industry, and from the form of its
races it is called the cup-and^one ball bearing.
Such a bearing is shown in cross-section in
Fig. 22, the one illustrated being the inside 'Y
front-wheel bearing used in the Maxwell **25"
car. Bearings of the type illustrated are not
regularly on the market, but are either made
by the automobile manuf actiu-er himself or to
his order.

The cup a forming the outer race is so shaped
that it comes in contact with each ball at two
points, as at 6 and c; the cone d forms the
inner race and is in contact with each ball at
a point. There are thus three points of con- ^'°" ^

tact for each ball, whence the name three-point ball bearing is
derived. A groove is turned in the outer race, into which is
spnmg a split retainer ring ^, the purpose of which is to retain
the balls in the cup when the cone is removed. This bearing
can carry a thrust load in only one direction, which is indi-
cated by the arrow /. The cone in this particular case is the
stationary member of the bearing, and the cup the movable
member; but in other cases the cup is the stationary member.

With the ordinary cup-and-cone ball bearing, it is customary
to fill the space between the cup and the cone with as many
balls as it will hold; that is, to make it a full-type bearing.

Digitized by

Google

36 BEARINGS AND LUBRICATION § 10

51. The application of the cup-and-cone type of bearing
to the front wheel of the Maxwell **25*' car is shown in Fig. 23,
in which a is the steering-knuckle spindle formed integral with
the steering knuckle. The inside bearing is shown at b and the
outside bearing at c. The cups of both bearings are pressed
into the hub d of the front wheel; the cone of the inside beariaig
is pressed on the spindle a against a shoulder formed thereon.
The cone e of the outside bearing is threaded internally to fit
a thread of the spindle, and by turning it in or out the two
bearings are adjusted. After adjustment the cone e is locked
in place by a locknut / of the castellated type and a washer g.

This washer is prevented
from rotating by a lug
that is formed integral
with it entering a longi-
tudinal slot cut into the
threaded part of the
spindle. Rotation of the
cone e while setting up
the locknut is thus pre-
vented by this washer g.
The castellated locknut /
is positively locked to the
spindle by the cotter pin h
passing through a slot of
the nut and through the
^®-^ spindle. The steering

knuckle shown is of the reversed Elliott type, that is, the
spindle and yoke are one piece and the end of the axle bar is
pivoted in the yoke.

On first thought it would appear that the wear of the cups,
cones, and balls could be readily compensated for in cup-and-
cone ball bearings by adjusting the one cone. This is not pos-
sible, however, except to a very slight degree, because the cones
wear out of round, a groove being formed on the loaded side,
which groove is deepest at the point where the load is greatest.
A pair of cup-and-cone ball bearings combined, as in Fig. 23,
gives an assembly that will resist thrust in opposite directions.

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 37

62. A radial-and-thrust ball bearing made by the New
Departure Manufacturing Company imder the name of the
Radax ball bearing, which takes thrust loads in only one direction,
is shown in Fig. 24. The bearing is of the two-point contact,
silent type, being fitted with a ball separator. In (a) the
bearing is shown in section, the balls being in contact with
the inner race a at 6, and with the outer race c at d. At e the
separator is shown in section. The races are so made that the

(b)

(c)

Pig. 24

two points of contact of each ball lie on a cone whose apex is
on the center line of the journal; under this condition the balls
have a true rolling motion. In view (b) are shown in perspec-
tive the inner race a and the outer race c and also the separator e
with the balls in place. The separator is made of steel and
in two parts, which are riveted together after the balls and
separator have been assembled over the inner race; the sep-
arator, balls, and inner race are then a unit. In (c) the bearing
is shown completely assembled.

Digitized by

Google

38 BEARINGS AND 1.UBRICATI0N § 10

Radax bearings are made to interchange with standard
radial annular bearings.

63. The New Departure double-row hall bearing shown in
Fig. 25 is intended for combined radial and thnist loads, and
can take thrusts in opposite directions. It greatly resembles
two Radax bearings assembled back to back into a single
structure. In (a) the bearing is shown in perspective, but
partly in section, and in (fc) the complete assembled bearing
is shown. In {c) a cross-section of the bearing is given. The
same parts are lettered alike in the three views. The inner

(a) (b) (c)

Pig. 25

race a is solid and has two grooves, or raceways, so laid out
that each ball makes contact with it at only one point. There
are two separate outer races b and c, which are also made
so that 'each ball touches them at only one point; hence, each
inner and outer raceway, together with their balls, form a two-
point bearing. The balls are placed in a manganese-bronze
separator d made in two halves. The whole bearing is assem-
bled into a single imit by spinning a steel shell e over the outer
races. After the shell has been spim over, its outside is ground
perfectly concentric with the bore of the bearing. It is obvious
that this double-row bearing is non-adjustable, although the
wear may be taken up by putting in larger balls. The success
obtained in practice from this form of bearing is largely due to
its non-adjustability.

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 39

New Departure double-row ball bearings are made to the
same dimensions, so far as inside and outside diameters are
concerned, as standard radial annular ball bearings; they are
much wider, however.

BALL THRUST BEARINGS

54. In automobile work are used two forms of ball thrust
bearings that may be classified as plain and self-alining thrust
bearings. Either class may belong to the silent or the full
tjrpe of bearing.

55. A plain ball thrust bearing of the silent type, as made
by the Standard Roller Bearing Company, is shown completely
disassembled in Fig. 26 (a). It consists of two grooved hard-

Pig. 26

ened-steel races a and fc, between which is placed the ball cage c
' containing the balls. In the ftdl type, no cage is employed.
Both the full and silent types are sometimes assembled with a
retaining band d around them, as shown in view (6), so that
the races and balls cannot come apart when\the bearing is
removed from its place. In the plain ball thrust bearing,
careful machining of the seats for the two races is relied on to
distribute the thrust load evenly over all the balls; it is evident,
however, that the slightest springing of shaft or housing will
throw all the load on one or two balls.

' 56. Sclf-alining ball thrust bearings are so constructed
that they will automatically adjust themselves in such a manner
that the thrust load at all times is carried by all the balls.

Three constructions are in use for making a ball thrust
bearing self -alining. In one, shown in Fig. 27 (a), a leveling,

Digitized by

Google

BEARINGS AND LUBRICATION

§10

(a)

(d)

Fig. 27

or radius f washer a is placed
on one side of a plain ball
thrust bearing. One side
of the radius washer is
flat, and the other side
is curved, so as to form
part of the surface of a
sphere. This curved side
of the radius washer is
placed against a similarly
curved seat; hence, the
whole bearing can rock
slightly to acconmiodate
itself to any disalinement.
In one form of a Hess-
Bright self-alining thrust
bearing, shown partly in
section in (6), one race a
has a flat outer surface and
the other race 6, a curved
outer surface forming part
of the surface of a sphere
whose center is on the

I center line of the bearing.

Sa radius washer c having
a curved inner surface and
a flat outer surface fits
against the race 6. The
balls are set in a cage d, this
bearing being of the silent
type. A retainer band
placed on the outside allows
the bearing to be readily
handled. In (c) the two
races a and b and the ball
cage d, with its balls, are
shown separately. The type
of self -alining thrust bearing

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 41

shown in (6) and (c) is placed between flat shotdders, or seats,
at the point where it is applied.

In {d) is shown in cross-section a ftdl type of self-alining
thrust bearing, as used occasionally around the pivot pins of
steering knuckles. Here, the one race a is curved on its outer
surface to fit a spherical seat.

All self-alining thrust bearings are made a very loose fit over
the shaft they surround.

57. Ball thrust bearings, when employed in automobile
work, are fotmd at one or both sides of the differential in rear
axles, on the driving pinion shaft of the rear axle, at the clutch
releasing collar, in steering knuckles, and in steering gears; in
short, they are found wherever a heavy thrust is to be resisted
by a rotating member of a car.

Ball thrust bearings are often employed in conjimction with
either radial ball bearings or cylindrical roller bearings and in
places where both a radial and a thrust load are to be carried
by a rotating member. They are not employed as a general
rule in conjimction with tapered roller bearings or cup-and-
cone type of ball bearings, as both of these classes can carry
thrust loads.

Digitized by

Google

Digitized by VjOOQ IC

BEARINGS AND LUBRICATION

(PART 2)

LUBRICATION

LUBRICANTS

DEFINITIONS

!• Lubrication consists in introducing some substance,
either liquid or solid, between two rubbing siuf aces, to reduce
the friction and the wear that otherwise would occur. No
matter how smooth a metallic surface may appear to the sight
or to the touch, it is in reality covered with very minute pro-
jections or ridges and hbllows. These are readily seen under a
microscope. Hence, when two clean metallic surfaces are
placed together and one is made to slide or roll upon the other,
these little ridges engage one another, or interlock, with the
result that some of the projections are torn loose from each
piece. It is this tearing away or abrading of the metal that
caxises wear, and the resistance thus offered is known ^s friction.

When a lubricating substance, or lubricant, is put between
the two surfaces, it fills the little hollows and forms a thin film,
or layer, that prevents the metals from actually touching each
other except at the points of the highest ridges. As a result
there is less wear, as a smaller nimiber of ridges are torn loose,
and this means less friction also.

The lubricants used in automobile practice are oils, greases,
graphite, mica, French chalk, etc. Oil is a liquid lubricant;

OOPYIUaHTKO BY INTKRNATIONAI. TKXTBOOK COMPANY. ALL RIGHTS RKSKRVKD

§10

Digitized by

Google

44 BEARINGS AND LUBRICATION § 10

grease is a semiliquid lubricating substance; graphite, mica,
French chalk, etc. are solid lubricants.

2. Oil is used for the lubrication of the engine and mis-
cellaneous small bearings outside the engine, it being customary
to use an engine oil suitable for the cylinders for the lubrication
of all the engine bearings and also for all other small bearings
around the car where oil is called for. An oil suitable for
cylinder lubrication of gasoline engines is known as a gas-engine
cylinder oil; cylinder oils suitable for steam engines are utterly
unsuited for gasoline engine cylinders, but are often employed
to advantage for transmissions and rear axles for lubricating
their gears and antifriction bearings. All automobile cylinder
oils are of mineral origin, having been distilled from crude oil.

Grease is used for bearings where the pressure due to the
load is relatively high, such as the spring shackle bolts, steering-
knuckle pivot pins, brake connections, etc. It is also used to
lubricate the antifriction bearings of front wheels and of the
rear wheels of three-quarter and full-floating rear axles, it
being the usual practice to pack the hubs full with a suitable
grease. Some quite fluid greases are used for lubricating
transmissions and rear axles; the transmission case or differ-
ential housing is then partly filled with grease.

Graphite, as well as mica in the powdered form, is mixed
with oil or grease to render it more unctuous. Flake graphite
is generally considered to be unsuitable for cylinder lubrication,
as it does not stay in suspension in oil but settles to the bottom.
So-called deflocculated graphite, sold under the trade name of
Oildag, however, is in so finely divided a state that it stays
mixed almost indefinitely with gas-engine cylinder oil; this
mixttu^ is occasionally used for automobile-engine lubrication.
There is also a very finely groimd dry graphite on the market
that stays mixed with cylinder oil for quite some time. Instead
of mixing graphite with the cylinder oil, the graphite may be,
and is, introduced occasionally directly into the cylinders,
being fed in a finely powdered form into the intake manifold,
whence the fresh charges passing through this manifold carry
the graphite along to the cylinders.

Digitized by

Google

§ fO BEARINGS AND LUBRICATION 45

Dry graphite, French chalk, talc, and soapstone, in powdered
fonn, are used as a lubricant between inner tubes and casings
of tires and are applied to rims to prevent tires sticking to them.

ACTOMOBILE-ENOINE CTLINDEB OIIi9

3. There are four properties that a good automobile-
engine cylinder oil should possess:

1. It should have as high a fire test as possible; that is, the
temperature at which it gives off inflammable vapor should
be as high as possible. In the best automobile-engine cylinder
oils this temperature will be from 450° F. upwards, which is
none too great considering the temperatures to which the oil
is subjected when exposed to the burning charge in the cylinder.

2. As the oil is vaporized by the heat, it should leave as
Httle residue as possible. Any cylinder oil will leave some
carbon deposit, which gradually accumulates on the inner
walls of the combustion chamber and on the piston head and
valves, but it is desirable that this accumulation should be
prevented as far as practicable. If it becomes thick, espe-
cially if the compression is high or if the form of the com-
bustion chamber is such that sharp comers are exposed. to
the heat of the flame, particles of the tmbumed carbon clinging
to the walls or elsewhere may become heated to such a degree
as to ignite the charge spontaneously before compression is
complete.

3. The oil must have good lubricating qualities, which may
generally be taken to mean that it has sufficient viscosity;
in other words, that it is not excessively thin. On the other
hand, however, the cylinder oil should not be very thick, else
it will not satisfactorily lubricate the bearings of the crank-shaft
and connecting-rods.

4. Oil used for lubricating any part on automobiles should
contain no acid. The presence of any acid is dangerous to the
metal parts, as it attacks and corrodes them. The corroding
action of an add is especially objectionable when ball bearings
are used. The surfaces of the balls and the races on which
they are run must be exceedingly smooth in order to give good

222B-42

Digitized by

Google

46 BEARINGS AND LUBRICATION § 10

service. If these surfaces are injured by corrosion, the life
of the ball bearings will be greatly shortened.

4. For ordinary water-cooled engines, some engine makers
recompiend the grade of cylinder oil known as heavy for summer
use. In weather cold enough to cause this oil to stiffen, the
next lighter grade, or medium, may be employed. In cold
weather it is the custom to use a special oil that will not become
too thick at low temperatures. Other engine makers recom-
mend that the same kind of oil be used all the year aroimd.
On account of this difference of opinion, it is advisable, when in
doubt as to what grade of oil to use, to inquire of the nfianu-
facturer of the car or the engine, who usually will be glad to
advise what brand of oil he recommends for his engines. This
information is also often given in the instruction books furnished
by many car manufacturers.

For air-cooled cylinders, only the heaviest oil obtainable
and with the highest possible fire test should be used. Many
oil refineries make a special oil suitable for air-cooled engines,
which is put up in tin cans plainly marked to that effect. Oil
suitable for water-cooled engines does not have a suflSdently
high fire test to permit its use in air-cooled engine cylinders,
where the cylinder temperature is very high.

6. If an automobile-engine cylinder oil is Ught or thin,
more of it must be used than of a heavy oil to accomplish the
same result, as the light oil is more easily decomposed by the
heat in the cylinder than is the heavy oil. The object is to feed
enough oil to insure perfect freedom of running and little wear
of the piston and rings. At the same time, it is well to avoid
the use of more oil than is necessary, as this will result in the
formation of carbon deposits from the burned oil, and a con-
sequent tendency to preignition, clogging of the valves, sooting
of the spark plugs, etc. In any case, only a high grade of min-
eral cylinder oil should be used, as the troubles that follow the
use of an inferior oil will more than offset the slight saving in
cost.

Some manufacturers of automobiles sell oils, marked with
their own labels, that they recommend for use in their engines.

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 47

These oils may generally be used with confidence in any engine
of about the same character as that for which they are put up.

6. As an example of what are considered suitable oils for
automobile engine use, the specifications of the Cadillac Motor
Car Company are here quoted:

For use in winter, oil should have a specific gravity of 30* Baum^ or
higher, that is, between 30* and 32*; flash test should be 415* F. or highet ;
fire test should be 470* F. or higher; viscosity should be 90 or higher
at 212* F. (Tagliabue viscosimeter) ; cold test 20* F.

For summer, the oil should have a specific gtevity of 29* Baum6 or higher;
flash test should be 435* F. or higher; fire test should be 480* F. or higher;
viscosity should be 100 or higher at 212* F.; cold test should be 30* or
higher.

Light, well-filtered oil is preferable. Dark oils usually contain more
carbon than light oils.

The Society of Automobile Engineers has drawn up the fol-
lowing specifications for a light automobile-engine oil:

Oil for this purpose must be a pure mineral oil, no addition or adulterant
of any kind being permitted. The following characteristics are desired:
specific gravity, 28* to 32* Baum6; flash point, not less than 400* F.; fire
test, not less than 450* F.; viscosity at 100* F., Saybolt viscosimeter,
not over 300 seconds; viscosity at 210* F., Saybolt viscosimeter, 40 to
50 seconds; viscosity at 210* F., Tagliabue viscosimeter, 60 to 65 seconds;
carbon residue, not over .5 per cent.

7. When an oil is heated, a temperature is reached at which
the vapors given oflf can be ignited with a lighted match or any
other flame. When these vapors ignite in flashes showing a
slight bluish flame, the temperature at which this occurs is
the flasli pointy or flasli test, of the oil. When the oil is
heated more, a temperature is reached at which the vapors bum
steadily ; the temperature at which this occurs is the fire point,
or fire test, of the oil.

The cold test of an oil is the temperature at which it will
not flow freely from a vessel.

8. The viscosity of oils is the degree of fluidity of an oil;
it is measured by an instrtmient called a viscosimeter. The
two viscosimeters in most common use are the Saybolt and the
Tagliabue instrtmients. Both of these, in conjunction with a

Digitized by

Google

48 BEARINGS AND LUBRICATION § 10

stop-watch, give the time reqidred for a certain quantity of oil
at a known temperature to flow through a nozzle of a given size.

The Saybolt viscosimeter is used only by the Standard Oil
Company, and by nobody else; when it is used it expresses the
viscosity by the number of seconds it takes 60 cubic centi-
meters (3.66 cubic inches) of the oil to pass through the measur-
ing nozzle of the instrument. Thus, if it takes 46 seconds to
discharge 60 cubic centimeters of oil having a temperature of
210° F., the viscosity is 4^ at 21(f F, on the Saybolt instrument.

The Tagliabue viscosimeter is used by independent oil
refiners. The viscosity of oil tested by it is indicated, in prac-
tice, in two ways. In the one case, the viscosity is taken as
twice the number of seconds it takes 60 cubic centimeters
(3.06 cubic inches) to pass through the measuring nozzle;
thus, if a sample of oil tested at 210° F. takes 46 seconds to pass
60 cubic centimeters through the nozzle, the viscosity is 90 at
21(jP F. on the Tagliabtie instrument. In the other case, the vis-
cosity is expressed directly as the ntmiber of seconds it takes
60 cubic centimeters to pass the nozzle; thus, taking the same
case as before, the viscosity is 45 seconds at 21(f F. on the
Tagliabue instrument.

The different viscosimeters in use do not register viscosity
alike; consequently, when the viscosity of an oil is given, it
must be known with what instrument it was measured.

9^ There are no simple tests by which an automobile owner
or driver can determine for himself whether or not oil that has
been or is to be purchased is of a high grade or not. In practice,
the recommendation of the manufacturers is generally followed
to advantage; in the absence of that, the quality of an oil can
usually be gauged quite accurately by its price. If the price
of a cylinder oil is abnormally low in comparison with what is
asked for well-known standard brands of oil, the quality of that
oil, as a general rule, is also low.

Digitized by

Google

(
§ 10 BEARINGS AND LUBRICATION 49

AUTOMOBILB GREASES

10« The greases used in automobile work are made in.
diflFerent consistencies to suit different climatic conditions and
service. As a general rule, each brand of grease is made in
three consistencies, often known as hard, medium, and light
grease, although some makers manufacture five consistencies
and give each an identification number. A distinction is
usually made between cup greases, which are intended to be
used in compression grease cups, and transmission greases,
which are often called non-fluid oils. Transmission greases
are very soft and fluid and, as implied by their name, are
intended to be used in automobile transmissions and rear-axle
housings to furnish a suitable lubricant for their gears and bear-
ings; they are entirely too fluid to be used in grease cups.

The viscosity of many cup greases is greatly affected by the
temperature to which they are subjected, the greases becoming
more fluid as the temperature rises and less fluid as it becomes
lower. With such greases, a hard grade should be employed
in summer, a medium grade in the spring and fall of the year,
and a light grade in winter, in order that the grease may be fed
freely from the grease cups. Some cup greases are affected
but little by temperature changes, and then the same grade
may be used all the year arotmd.

Greases are manufactured in different consistencies, not only
to suit different climatic conditions, but chiefly to suit different
pressures on the bearings they lubricate. A hard grease is
suitable for high pressures and a light grease for low pressures.

!!• Flake graphite, and also groimd mica, are sometimes
added to greases to increase their lubricating qualities. Graph-
ite greases are made in various consistencies and are qtiite
frequently employed for grease cups; mica greases are seldom
used in automobile work. A graphite grease mixed with cedar
sawdust is sometimes employed in sliding-gear transmissions
that have become imduly noisy from abnormal wear of the gears;
the sawdust seems to act as a cushion between the teeth, deaden-
ing the noise. As in the better grade of modem cars the wear

Digitized by

Google

50 BEARINGS AND LUBRICATION § 10

of gear-teeth and transmission bearings is quite slight, the lase
of combined grease and sawdust in transmissions is tmcommon
at present.

The use of grease in transmissions and rear axles is not as
common now as formerly, many automobile manufacturers
recommending the use of a heavy, steam-engine cylinder oil
instead. Ordinary, cheap, steam-engine cylinder oil is of
little value as a lubricant for transmissions and rear axles;
best results are usually obtain^ from a cylinder oil suitable
for superheated steam and having a fire test of about 600° F.

12. Some transmission greases are of a fibrous nature and
ding to the gears with great tenacity; better results are usually
obtained from such greases than from greases that are so fluid
that they will drip at once from the gears. Greases that are
so heavy that the gears simply cut a path through them are of
no value in transmissions, etc. ; by mixing them with gas-engine
cylinder oil, however, their consistency can often be reduced so
that they will give satisfactory service. A transmission grease
that is too light to cling to the gear-teeth can be thickened by
mixing it very thoroughly with a sufficient quantity of heavy cup
grease. As a general rule, however, it will be more satisfactory
to use a transmission grease of the right consistency than to
attempt to obtain it by mixing as just described.

ENGINE LUBRICATION SYSTEMS

CLASSIFICATION

13« The many diflferent sjrstems by which the moving
parts of automobile engines are supplied constantly with oil
while the engine is at work can be broadly divided into splash
lubrication systems, pressure-feed lubrication systems, and com-
bined splash-and-pressure-feed lubrication systems.

14« In a splash lubrication system, the lower part of
the crank-case contains cylinder oil into which the lower end

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 61

of the connecting-rods dip at every revolution, churning the
oil into a dense mist and throwing it all over the internal sur-
faces of the engine. There are three general divisions of this
lubrication system in existence.

The simplest one is the variable-level splash system. In this,
oil is poured periodically by hand into the lowei
and consequently the oil level is continually chan^
fillings. Owing to the constant attention required
is now obsolete.

The second general division is known as the autom
level splash system. As implied by the name, the
into which the connecting-rods dip is maintained a
at a constant, or virtually constant, level by oil t
separate oil reservoir, which most commonly is
in the*crank-case.

The third general division is known as the self -a
splash system. In this system, as tisually carried ov
oil is continually pumped into movable trough
connecting-rods, the troughs being interconnect
throttle valve in such a manner as to bring the
the connecting-rods when the throttle valve is oj

IS. The constant-level splash system is divid<
general classes, in accordance with the manner i
oil is kept at a constant level. The first class is 1
vacuum-feed constant-level splash system. In thii
contained in an air-tight reservoir located so that
higher than the crank-case oil level. A sUght vi
above the oil in the reservoir, which is partiy decrea
the oil level in the crank-case drops a certain £
permitting oil to flow from the reservoir to th
until the sealing of the outflow pipes arrests the flc
the reservoir. This system has been used in nimier
Flanders, and Studebaker cars, and gives good results when care
is taken to have the oil reservoir air-tight.

The second class is known as the circulating constant-level
splash system. In this, the oil is transferred from a reservoir,
in much larger quantities than is needed, into troughs placed

Digitized by

Google

62 BEARINGS AND LUBRICATION § 10

beneath the connecting-rods, from which troughs the oil over-
flows hack to the reservoir, whence it is sent hack to the troughs
again. The oil is thus continually circulated. In some cir-
culating constant-level splash systems, individual troughs
are used, one being placed under each connecting-rod; the oil
reservoir is then in the bottom of the crank-case and is open
at the top. In other systems, the oil reservoir, when in the
bottom of the crank-case, is closed on top by a horizontal parti-
tion in which the troughs are formed, each trough having an
overflow through which surplus oil flows back to the reservoir.
The third class of splash lubrication system is spoken of as
the noip-ctrculating constant-level system. In this S3^tem, oil
is taken from a reservoir by a ptamp and delivered, in the right
quantity, to troughs into which the ends of the connecting-rods
dip. The oil reservoir may form part of the crank-case or be
entirely separate from it; the deUvery of the ptamp is usually
adjustable, and fresh oil is delivered to the splash troughs at
all times, in which respect this sjrstem differs from the circulating
system.

16. In a pressure-feed lubrication system, as implied
by the name, the oil is supplied to the rubbing surfaces under
pressure.. In the strictest sense, the oil would be supplied to
all rubbing surfaces under pressure; as carried out, however,
oil imder pressure is usually supplied only to the crank-shaft
main bearings, crankpins, wristpins, and timing gearing. The
oil thrown off from the crank-pins is usually relied upon to
lubricate the cam-shafts, cylinders, and other rubbing surfaces.

Pressure-feed lubrication systems are divided into two
classes, the first one of which may be called a low-pressure
lubrication system. In one subdivision of this dass, oil lying
in the bottom of the crank-case is ptimped continually into an
elevated tank, whence it flows under the low pressure due to
the elevation of the tank through individual pipes to the various
bearings, whence it drains to the bottom of the crank-case and
is pimiped back again to the tank. This is also known as the
De Dion oiling system, and was used for a long time, among
others, on the engines of the Pierce-Arrow cars. In another

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 53

subdivision, no ptunp is employed. The oil is contained in an
elevated tank and passes through adjustable sight-feeds and
individual pipes to the various bearings, in some cases only
under the influence of gravity, but in others under a slight
pressure derived by connecting the top of the oil tank with
the exhaust pipe of the engine; the used oil is not returned
to the tank. In yet another subdivision, used in some models
of the Hupmobile car, the fl3nvheel of the engine dips into oil in
the reservoir and carries it to an elevated point, whence the oil
flows, partly by gravity and partly by pressure due to centrifugal
force, to the bearings and cylinders.

In the high-i^ressure lubrication system, oil is taken from a
reservoir, usually in the bottom of the crank-case, and delivered
by a pump or pimips under pressure ranging from 3 to 16 pounds
per square inch to the various bearings; in racing cars much
greater oil pressures are often used. In present-day practice, a
single pump is employed, which discharges into a manifold from
which branch pipes lead to the various bearings ; individual pumps
for each bearing have been employed, however, in many cars.

17. In combined splasli-and-pressure feed lubrica-
tion systems, many different combinations of the various
forms of splash and pressure systems are possible and have
been used. A common form employs pressure feed to the main
crank-shaft bearings, the overflow from these bearings flowing
into troughs below the connecting-rods, from which the crank-
pins, wristpins, cylinders, etc. are lubricated by splash lubrica-
tion. In another S3^tem, oil is supplier! only to the cylinders
imder pressure; all the bearings are lubricated by the splash
system. Other combinations than those enimierated here may
be used.

SPLASH LUBRICATION SYSTEMS

18» In Fig. 1 there is shown, partly in section, the crank-
case a and oil reservoir b of the engine used in the Studebaker
"20" car, in which a vacuum-feed, constant-level splash
lubrication system is employed. The oil reservoir i& filled
through a removable cap c] the bottom of the reservoir is

Digitized by

Google

-^^~JStf

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 65

connected by two pipes d to points near the bottom of the
crank-case. A chedc-valve e fitted with a spring/ on its xinder
side, and a long stem g is raised by its spring when the cap c
is unscrewed from the reservoir, and thus shuts off the reservoir
from the crank-case while the former is being filled with oil.
The act of replacing the cap c opens the check-valve e. The
oil reservoir is fitted with a gauge glass h, which shows the
height of oil in the reservoir.

The action of the vacuum feed is as foUows: Normally,
with the engine at rest, oil has flowed from the reservoir b
into the two compartments of the crank-case imtil the oil
level just covers the outlets of the pipes d. The oil reservoir
being air-tight, a partial vacuum is formed above the oil in
this reservoir through the oil flowing therefrom. As soon as
the outflowing oil covers the outlets of the pipes d, the flow
of oil from the reservoir stops, the partial vacuum above the
oil now being great enough to prevent oil from flowing from the
reservoir. When the engine is started, the coimecting-rods
dip into the oil in the two compartments of the crank-case,
there being one oil compartment for each two cylinders, and
splash oil all over the inside of the engine. Consequently,
the oil level in the two compartments falls below the outlets of
the pipes d, and air will bubble through the oil in these pipes
and the oil in the reservoir to the upper part of the latter,
thereby lowering the vacuimi until the pressure of the atmos-
phere is insufficient to hold the oil back. Oil now flows into
the crank-case compartments imtil the outlet ends of the pipes
are sealed once more, when the flow of oil from the reservoir
stops again. This cycle of operations is repeated over and over
again, whenever the oil levd in the crank-case falls below the
outlets of the oil pipes d.

As the operation of the vacutmi feed depends entirely on
the maintenance of a vacuum in the reservoir, the greatest of
care must be exercised to have the filler cap and also the gauge
glass fittings make air-tight joints.

Two drain cocks i with extension pipes / are used for bringing
the oil to its proper level, which is even with the open end of the
extension pipes. If it is desired to entirely drain the two oil

Digitized by

Google

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 57

compartments, the two cocks with their extension pipes must
be completely unscrewed from the bottom covers k of the oil
compartments.

19. The oiling system used in the engine of the Ford,
model T, automobile is the simplest form of a circulating
constant-level splash system, and is characterized by the
absence of a pump for circulating the oil ; it is shown in Fig. 2.
There are three troughs a formed in a removable plate at
the bottom of the crank-case fc; in the earlier model T engine
these troughs were formed directly in the crank-case. The
connecting-rods of the first, second, and third cylinders dip
into oil with which these troughs are continually being filled,
splashing this over the cylinders and bearings. To the rear
of the lower crank-case b is the lower flywheel and magneto
housing c, and to the rear of this the lower clutch and trans-
mission housing d, both of which are in one piece with the lower
crank-case. The lower housing c forms the oil reservoir, which
is supposed to be filled with oil to the level of the upper gauge
cock e, and to be refilled as soon as the oil level has dropped
below the level of the lower gauge cock /. This oil reservoir
is filled by pouring oil through the crank-case breather pipe g,
whence it flows along the bottom of the crank-case b to the
reservoir c. The cap shown covering the breather pipe has
openings in it commtmicating with the atmosphere; these
openings cannot ^e seen in the illustration. The flywheel,
with the horseshoe-shaped magnets of the magneto that
are attached to it, dips into the oil in the housing c, and
when the engine is running throws oil into the upper flywheel
housing h. Some of the oil drops by gravity into the fun-
nel-shaped opening of the oil circulation pipe i, shown in
dotted lines, which leads to the timing gears at the forward
end of the engine, whence it drops to the forward end of
the lower crank-case and in flowing back to the reservoir c
keeps the three troughs a filled. The fourth cylinder, together
with its working parts, is lubricated by splash directly from the
reservoir c. Some of the oil thrown into the upper flywheel
housing h flows to the rear, oiling the transmission and imiversal

Digitized by

Google

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 59

joint of the driving shaft, returning along the sloping bottom
of the transmission housing d to the reservoir c.

20. The circulating constant-level splash oiling system used
in the engines of some Buick automobiles is shown in Fig. 3.
In this lubrication system, a gear-pump is employed for cir-
culating the oil. The oil reservoir a is formed in the lower
crank-case and has fitted to it, at its rear end, the oil pump 6.
The oil in the reservoir flows to the oil ptmip through a screen c,
whereby it is strained, and is pumped through a pipe (not
shown) connected to the passaige d of the oil pump to a sight
feed and then flows through the pipe e^ which is on the outside
of the left sid6 of the crank-case, and four nozzles /, to the
four oil troughs g. These oil troughs are formed in a horizontal
partition and are located directly beneath the connecting-rods.
The oil in the troughs is kept at a constant level by the oil
pump delivering a larger quantity than is needed; the excess
oil overflows the troughs through the openings h and drains
back into the reservoir a to be circulated again. The oil
pump in this case is driven from the engine cam-shaft i by bevel
gears. The driving shaft ; of the oil pump is made in two parts
that are connected by a helical spring ky which acts as a tmiversal
joint and hence takes care of any lack of alinement between the
two parts of the shaft. The driving shaft is made in two parts
to permit quick and easy removal of the oil pump. The timing
gears are lubricated by splash from the crank-case.

21. In Fig. 4 is shown the circulating constant-level
splash lubrication system used in the engine of the model 36
Studebaker car. The system here shown differs from that
used in the Buick engine, and described in Art. 20, in that a
plunger pump is used instead of a gear-pump and, further, in
that a separate oil lead keeps the timing and magneto gears
flooded with oil. Another point of difference is that the
pump sprajrs oil directly on the lower ends of the connecting-
rods, instead of delivering the oil into the troughs under them.
Referring to the iQustration, the oil reservoir a is in the base
of the lower crank-case 6, and the four oil troughs c are in a
horizontal partition in the lower crank-case. Overflow holes

Digitized by

Google

60 BEARINGS AND LUBRICATION § 10

are provided alongside of each trough, through which all excess
oil drains back to the oil reservoir. The plunger pump d
is operated by an eccentric on the cam-shaft, and takes its oil
supply through the pipe e from the bottom of the oil gauge /,
which shows the height of the oil in the reservoir. The pump
has two oil delivery pipes; the pipe g leads to the sight-feed
glass h on the dashboard of the car, whence the oil flows by
gravity through the pipe i to the magneto driving gears and
timing gears. The second oil delivery pipe ; connects to an oil

Pig. 4

distributing pipe placed horizontally inside of the crank-case
and which has four holes k in line with the crankpins; the
oil is squirted imder pressure over the crankpin bearings.
All excess oil drains back to the four troughs, into which dip
splashers at the end of the connecting-rods.

22. In some circulating constant-level splash systems,
oil is pumped to one or more bearings in addition to, perhaps,
the timing gearing and other bearings, but the oil does not
circulate through these bearings under pressure, and hence

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 61

such systems are not classified as combined pressure-feed and
splash systems. Sometimes more than one oil pump is used;
thus in the Continental, model C engines, two plimger oil
pumps are fitted, one of which pumps oil over the timing gears;
whence it flows to the two forward splash troughs, while the
second pumps oil to the rear main crack-shaft bearing, whence
the oil flows to the two rear splash troughs. In Rutenber
engines, the oil is forced by a single ptamp of the gear-type into

(«)

Fig. 5

a distributing pipe having holes that direct streams of oil to all
the crank-shaft bearings, the oil draining to splash troughs
and through overflow openings back to the reservoir in the
bottom of the lower crank-case, whence it is circulated again.
The oil does not pass into and through any bearings imder
pressiu-e, however, but is merely directed to them in a positive
manner. Splashers at the lower end of the connecting-rods
dip into the splash troughs, splashing oil all over the inside of
the engine.

222B— «3

Digitized by

Google

62 BEARINGS AND LUBRICATION § 10

23. A non-circulating, constant-level splash lubrication
system is used in the four-cylinder engine of the Cadillac cars,
in the four- and six-cylinder Northway engines, and in others.
In Fig. 5 (a), a cross-sectional view of the lower crank-case and
part of the upper crank-case of the Cadillac engine, with the
crank-shaft and part of the connecting-rod in ^x)sition, is
shown. View (6) is a perspective of the lower crank-case
removed from the engine. Like parts are lettered the same in
both views, and both illustrations should be referred to in
reading the description. The lower crank-case is divided by
four partitions a into fotu: compartments, one beneath each
connecting-rod; at the front of the crank-case is a fifth com-
partment b which may be called the oil equalizing well. Splash
troughs Cj into which scoops at the lower ends of the connecting-
rods dip, are formed in the bottom of the crank-case. These
splash troughs are supposed to be practically full while the
engine is at rest; any excess oil can be drained off by removing
the drain plugs d. The splash troughs themselves can be
drained by taking out the drain plugs e. On the right-hand side
of the upper crank-case, and cast integral with it, is an oil
reservoir fitted with two plimger pirnips. One of the oil pumps
forces oil from the reservoir to a sight-feed glass on the dash-
board, whence the oil flows by gravity to the suction side of the
second oil pump, which pumps the oil into a distributing pipe
that supplies the lower crank-case with oil.

The four partitions a act as baffle plates that prevent the
oil in the lower crank-case from flowing forwards or rearwards
in a body and piling up at the front or rear end of the crank-
case when the car is descending or ascending a hill. To prevent
the oil in the crank-case from gradually piling up in the front
or rear compartment, an automatic oil equalizing system is
fitted, which consists of four troughs / sloping downwards and
forwards, and an equalizing passage g that connects the oil-
equalizing well b with the rear compartment. The sloping
troughs / are on the right-hand side of the crank-case, and the
lower end of each of these troughs opens into the oil compart-
ment just forwards of it; thus, the sloping trough in the oil
compartment nearest the front coimects to the oil-equalizing

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 63

well 6. The excess oil thrown up by the connecting-rods
drains down the right-hand side of the crank-case into the
sloping troughs /, and thus gradually travels from the rear
compartment to the front compartment and thence to the oil-
equalizing well 6, whence it flows through the equalizing pas-
sage g to the rear compartment again. The oil is thus prevented
from piling up in front.

While the oil circulates from one compartment to the other
in this sj^stem just described, it is not a circulating system, there
being no oil returned to the reservoir. The pumps only
handle enough oil to compensate for the oil used and they
always handle dean oil.

24. When six-cylinder engines are fitted with a non-cir-
ctdating constant-level splash lubrication system and inclined
troughs are used for circulating the oil from one compartment
to the other, the troughs of the first three oil compartments may
slope forwards and those of the last three oil compartments
slope rearwards. An equalizing passage will then lead from
the first compartment of the crank-case to the fourth oil com-
partment, and another equalizing passage from the sixth
compartment of the crank-case forwards to the third oil com-
partment. This system is used in some six-cylinder Northway
motors.

Some engines using the non-circulating constant-level
splash oiling system use only one oil ptimp, which usually
discharges into a sight-feed glass on the dashboard or cowl-
board; the oil then flows to the splash troughs by gravity.

25. An example of a self-adjusting-level splash lubrica-
tion system is found in the engine of the model 72 Lozier car.
A top view of the crank-case of this engine is shown in Fig. 6 (a) ;
in (fc), a part sectional side view of the same crank-case is pre-
sented; and in (c), (d), and {e), one of the oil troughs is shown
in section in several positions and to a greatly enlarged scale.

The bottom of the lower crank-case forms an oil reservoir a
that is almost entirely closed on top by a horizontal partition 6,
which contains an oil gutter c along which all excess oil coming
from the oil troughs d flows back to the rear of the reservoir.

Digitized by

Google

BEARINGS AND LUBRICATION

§10

The six oil troughs d, into which scoops on the ends of the con-
necting-rods dip, are located above the partition 6, and are
hung on trunnions e at the right and left of the crank-case, on
which they can rock to and fro. Each oil trough has a crank-
arm /; the six crank-arms are all pivoted to a bar g, which in

turn is connected to the foot throttle lever, or accelerator, so
that any motion of the carbureter throttle, either by the hand
throttle lever or the accelerator, moves the bar g forwards or
backwards, thus turning each trough a corresponding amount.
A gear-pump, which is not shown, forces oil in large quantities
through the stand pipes h into the several oil troughs, which

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 65

are thus kept oontinuaQy filled, the oil overflowing the troughs
and returning to the reservoir.

With the throttle wide open, the engine is under a heavy load
and should receive the most oil; under this condition, the oil
troughs are in the position shown in (c), where they contain
the greatest quantity of oil. With the throttle moved to its
half-open position, the load is lighter and less oil is required;
the partial closing of the throttle has tilted the six troughs to
the position shown in (d). In tilting the troughs, the oil
therein overflows the lower edge i of the troughs until the oil
level is at this edge. The oil level now is farther away from
the crank-shaft, and consequently the scoops on the ends of the
connecting-rods do not dip so far into the oil in the troughs,
and hence less oil is splashed to the working parts of the engine.
Still less oil is splashed when the throttle is almost entirely
closed, when the troughs are in the position shown in {e).

26» A number of the Knight sleeve-valve engines used in
various cars employ an adjustable-level oiling sjrstem with
tilting oil troughs. The oil troughs are not tilted sidewise,
however, as in the Lozier engine, but are tilted endwise; or in
other words, they are brought bodily nearer to the crank-shaft
when more oil is needed. The troughs are connected to the
accelerator.

PRESSURE-FEED LUBRICATION STSTBMS

27. Low-Pressure Lubrication Systems. — ^The several
forms of lubrication systems in which oil from an elevated
tank separate from the engine is discharged imder a very low
pressure to the bearings, are now little used. As an example
of such a lubrication sjrstem, that used for a number of years
on the Pierce-Arrow car engines is shown in Fig. 7. An oil-
pump a of the gear-type draws oil from the bottom of the crank-
case b and discharges it through a pipe into the oil reservoir c,
which is made from sheet brass. This reservoir is located to one
side and slightly above the cylinders; its nearness to the cylin-
ders insures that the oil remains fluid even in the coldest
weather. From the bottom of the oil reservoir, seven oil pipes d

Digitized by

Google

Digitized by VjOOQ IC

68 BEARINGS AND LUBRICATION § 10

lead to the seven main bearings of the crank-shaft, the engine
shown having six cylinders; an eighth oil pipe e leads to the
tinwng gears, and a ninth oil pipe / leads to a gauge g on the
dashboard, which shows the amount of oil in the reservoir.
With the engine standing, the reservoir empties itself very
quickly, the oil draining back into the bottom of the crank-
case; after running a few nwnutes, however, the pump when in
order will partly fill the reservoir and the gauge g will show oil,
and thereby indicate the proper working of the oil pimip. The
oil flows to the main bearings and timer gears only under the
pressure due to the elevation of the oil reservoir, and is con-
veyed from the main bearings to the crankpins through pas-
sages h drilled in the crank-shaft. The oil enters the crank-shaft
through a radial hole i in the journals, registering once at each
revolution with a radial hole in the main bearing brasses, to
which holes the oil pipes d are connected.

Each oil pipe is fitted with a removable wire gauze strainer.
The oil thrown off from the crankpins is depended on to lubricate
the cylinders, pistons, piston pins, cam-shaft bearings, cams,
valve lifters, and other parts inside the crank-case. The
bottom of the oil reservoir slopes upwards at an angle of 25® at
the front and rear; this insures that the oil level over all the
inlets of the oil pipes will be practically equal, irrespective of
the grade of the road.

28. The low-pressure engine oiling system of the "32"
Hupmobile car is shown in Figs. 8 and 9, Fig. 8 being a right-
hand side view of the tmit power plant, partly in section, and
Fig. 9 a cross-section taken between the second and third cylin-
ders, looking toward the rear, with part of the third cylinder
broken away, and in some respects drawn in a conventional
manner. The same parts are lettered alike in both illtistrations,
and both should be referred to in reading the description.
The lower crank-case a is constructed so that its bottom slopes
to the rear, and its lower part serves as an oil reservoir, which
is normally filled with oil to the level shown. On a level road,
the ends of the connecting-rods do not dip into the oil, but on
steep descents the first connecting-rod may do so, although

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 69

the resulting splashing of the oil is not depended on in any way
to assist lubrication. The lower part of the flywheel b is enclosed
in a closely fitting oil pan c made from sheet metal, to which
the oil in the reservoir has access throtigh the holes d. As the
flywheel revolves in the direction of the arrow e, some of the
oil adheres to the flywheel rim and is carried around with it.
On the right-hand side of the upper crank-case and where it

Pig. 9

surroimds the fljnvheel, a horizontal rib / is formed, which is
machined so as to just dear the flywheel rim. This rib /
scrapes oflE most of the oil from the flywheel rim and forces it
to enter the passage g, from which an oil pipe h conveys it to a
strainers; the oil passes from the strainer to a regulating valve ;
and thence into a horizontal passage k, from which it passes
to the three main bearings through passages /. Diagonal holes m

Digitized by

Google

70 BEARINGS AND LUBRICATION § 10

leading to the crankpins are drilled in the cjrank-shaft so as
to register once each revolution with the passages /. The
main bearings and crankpins are thus lubricated under a sUght
pressure, and the oil spray thrown off from the bearings is
depended on ordinarily to oil the cylinders, piston pins, valve
lifters, cam-shaft, etc. The cam-shaft bearings are oiled by
oil thrown oflf the connecting-rods and main bearings and caught
in oil pockets n formed in the upper crank-case.

Two oil pipes o lead from th^ regulating valve ; to passages p ,
one being between the first and second cylinders, and the
other between the third and fourth cylinders. The two pas-
sages p open into the four cylinders and are so located that with
the pistons near the bottom of their stroke, they register with a
wide groove turned in the pistons at the piston pins. The oil
coming through the passages p thus can flow around the piston
and also into the hollow piston pins g, and, through the holes r
in them, lubricate their bearings in the piston. In this particu-
lar engine the piston pin is rigidly attached to the connecting-
rod, and is loose in the piston.

29. The regulating valve ; is in the form of a hollow cylinder
closed at one end and carrying a crank-arm 5, which is con-
nected to the accelerator pedal by rods t and a lever u\ any
movement of the accelerator, and hence of the throttle, partly
rotates the regulating valve in its casing. The regulating valve
has ports v and w in it, which come into register with similar
ports in its casing. The ports v connect with the oil pipes o
and passages p leading to the cylinder; the ports w connect
with the oil passage k, from which the oil flows to all the crank-
shaft bearings.

The object of the regulating valve is to supply oil in pro-
portion to the load on the engine. It is connected to the
accelerator in such a manner that when the throttle is about
one-quarter open, the ports w in the regulating valve begin to
open the ports in the casing of the valve, and oil begins to flow
into the passage k. As the throttle is opened farther, the ports a;
open farther, and more oil passes into the passage k. When
the throttle is about half open, the ports v begin to open the

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 71

corresponding ports of the casing, and oil now flows to the
oil pipes 0 and passages p and thence to the pistons and piston
pins.

The transmission x and universal joint y run in oil that is
thrown up by the flywheel against the upper flywheel casing
and trickles down the upper transmission casing. All excess
oil drains back from the universal-joint housing to the oil
reservoir through the pipe z. The oil supply in the oil reservoir
is replenished through the breather pipe a'; an oil gauge inside
the tube a" indicates the oil level in the reservoir.

30. High-Pressure Lubrication Systems. — Several
American cars employ a pressure-feed oiling system in which
the oil under quite a high pressure is deUvered to the various
crank-shaft bearings, and the oil thh)wn off these bearings in
the form of a fine mist is relied on to lubricate the cylinders and
various minor parts of the engine. Among the cars employing
this system may be mentioned the Marmon car and late models
of the Pierce-Arrow automobile.

The pressure-feed lubrication system of the Pierce-Arrow
engine is shown in Fig. 10. The bottom of the lower crank-case
forms an oil reservoir a, from which the oil is taken through
a strainer by an oil pimip b of the gear-type and discharged
through the pipe c into a second oil strainer d, from which the
oil passes through a pipe e into a distributing manifold/. This
manifold, through distributing pipes, is connected to the
forward bearing g, the naiddle bearing fe, and the rear bearing i
of the crank-shaft, which in the engine shown has seven main
bearings. A pipe ; leads irom the manifold / to the timing
gears fe, and a pipe / leads to a pressure gauge m placed on the
dashboard. The crank-shaft is drilled with radial holes n
and axial holes o through the various jotutials; holes p in the
crank-webs connect the axial holes o. From each crankpin end
of the connecting-rods an oil tube q leads to the piston pins r.
The excess oil drains back to the oil reservoir and is pimiped
back to the oil-distributing system. The oil reservoir is sup-
posed to be kept filled to the level of the test cock s\ it is filled
through the funnel t and drained through the drain cock w.

Digitized by

Google

Digitized by VjOOQ IC

§ 10 BEARINGS AND LUBRICATION 73

31. In most pressure-feed lubrication systems of the high-
pressure type and using a single pump, a relief valve is fitted;
this valve can be adjusted by hand to any pressure that will
produce satisfactory lubrication. Thus, if the engine smokes
continually it is getting too much oil; the obvious remedy is to
reduce the pressure in the oiling system until smoking ceases,
which is done by adjusting the relief valve to open at a lower
pressure. The relief valve acts by discharging some oil from
the delivery side of the oil pump back to the suction side. In
high-pressure lubrication sjrstems in which an individual
ptmip is used for each oil pipe, no relief valve is needed, as the
delivery of each pump is made adjustable; this system is now
quite rare in American practice.

COMBINED SPLASH AND PBESSUBE-FEED LUBRICATION SYSTEM

32« Lubrication systems making use of both splash and
pressure feed were very popular at one time, but have been
largely superseded by the constant-level splash system.
Where a combination system is tised, many different com-
binations are possible. Thus, in the model 69 Overland car,
a pressure-feed system is employed for the cylinders and timing
gears, and splash lubrication is used for the crank-shaft and
cam-shaft bearings and all other parts inside the engine. In
the engines of many Stevens-Duryea cars, pressure-feed by
individual plunger oil pimips is adopted for the main bearings
of the crank-shaft, and splash lubrication for all other parts of
the engine.

33. An external right-hand view and a cross-«ectional view
of the engine of the model 69 Overland car are shown in Fig. 11.
The lower crank-case a is divided into two oil compartments by
a crosswise partition near its middle, the forward compartment
serving as a common splash trough for the connecting-rods of
the first and second cylinders; the rear compartment serves the
same purpose for the third and fourth cylinders. Each com-
partment has a teUtale cock b carrying a stand pipe c; if oil does
not issue from the telltale cock when opened, oil must be added
until it does flow. When oil flows from the cock in a stream.

Digitized by

Google

BEARINGS AND LUBRICATION

§10

the oil level is too high and the cock must be left open until
the flow of oil ceases, which occurs when the oil level is even

Pic. 11

with the top of the stand pipe c. A mechanical oiler d, which
also forms the oil reservoir for the pressure-feed system, is

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 75

fitted at the right of the engine and with its top about level
with the top of the cylinders; owing to its being so near to the
cylinders, the oil it contains is kept fltaid even in the coldest
weather while the engine is running. Inside the oiler d are
six separate oil pumps, the delivery of each of which can be
adjusted independently of the others. The oil delivery pipes e
convey oil under pressure to the four cylinders; the oil pipe /
carries oil to the timing gears, and the oil pipe g to the rear
compartment of the crank-case. Oil from the timing-gear
case flows to the forward compartment.

Oil imder pressure enters at one side of each cylinder and is
distributed over the cylinder walls by three oil grooves turned
in each piston near its lower end. The six oil pimips are
intended to be adjusted by trial so as to supply just the same
amoimt of oil as is used up. If the cylinders receive too much
oil, as evidenced by gray smoke at the exhaust pipe and a very
oily combustion chamber, the oil supply to the cylinders is cut
down until smoke does not form; after the four oil ptmips for
the cylinders have once been adjusted, the adjustment for a
constant level in the oil compartments is made by adjusting
the stroke of the two plimger oil pimips serving the oil pipes
/andg.

LUBRICATING DEVICES

OIL PUMPS

34. The oil pumps used with engine-lubrication systems
can be divided into three general classes, which are gear-
pumps, plunger force pumps, and lifting pumps. Other classes
of pimips have been used in some rare cases, but, broadly speak-
ing, the three classes enumerated cover the oil pumps in actual
use.

A gear-pump consists of two spur gears in a suitable hous-
ing and driven by the engine; this form of pump is probably
more widely used than any other in lubrication systems employ-
ing a single pump, on account of its simplicity and reliability
of action.

Digitized by

Google

76 BEARINGS AND LUBRICATION § 10

In plunger force pumps, some rotating part of the engine
through an eccentric or a cam actuates a plunger fitting closely
in a barrel, and moving to and fro. Oil flows into the barrel
on the outward motion of the plunger and is discharged on
the inward motion. There are two general classes of plunger
force pumps for lubrication systems, which are the single-valve
class and the two-^alve dass. In the single-valve plunger
force pump, only the discharge is controlled by a valve; in
the two-valve class, the inlet and the discharge are each con-
trolled by a valve.

In lifting pumps, oil flows into the barrel on the outward
stroke of a piston, and is also discharged on the same stroke;
on the inward stroke, oil passes from one side of the piston to the
other through a valve in the piston itself.

35. Oil pumps used in automobile engines are often so
constructed that the quantity of oil delivered may be varied.
When a circulating constant-level splash system is employed, '
there is no need for an adjustable oil pump; with a constant-
level non-circulating splash system, an adjustable oil pump
is usually employed. In high-pressure lubricating systems,
it is generally considered advisable to control the oil delivery
in some manner.

When a gear-pump is employed, its oil delivery is controlled
by a relief valve capable of being set at different pressures, and
permitting some oil to flow back from the delivery side to the
suction side. With plunger force ptunps and lifting pumps,
which are incorporated in, and are positively driven from, the
engine, the most obvious way of varying the oil delivery is to
provide means for varying the length of the stroke. At one
time, it was common practice to combine the oil reservoir
and a number of oil pumps into a structure called a mechanical
lubricator^ which was entirely separate from the engine; the
pimips were then actuated from a shaft that derived its motion
through being belted to some rotating part of the engine. In
that case, in addition to providing means for adjusting the
length of the stroke of each ptmip, it was possible to vary the
quantity of oil delivered in a given period of time by making

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 77

the ptunps run faster or slower in relation to the engine speed;
this was done by changing the size of the driving or driven
pulleys, or of both, as was most convenient. Separate mechan-
ical lubricators are virtually obsolete at present; in modem
automobile practice, the lubrication system forms an integral
part of the engine.

36. In Fig. 12 is shown a top view, with the cover
removed, of the gear oil pimip used in the engine of the Chal-
mers **36*' car. There are two meshing spur gears a and b on
shafts having bearings in the housing c; the gear a is driven
from the engine in the direction of the arrow marked on it and
drives the gear b. The housing c closely fits one-half the cir-
cumference of each gear, and in conjunction with the two gears
forms an inlet chamber

at d and an outlet cham-
ber at e. The oil inlet
to the pump is at / and
communicates through a «
port g with the inlet
chamber d; the port h
in the outlet chamber e
commtmicates with the
oil outlet i, from which ^°- "

a pipe leads to a sight-feed glass on the dashboard of the car.
Rotation of the gears in the direction of the arrows marked
on them takes oil from the inlet chamber and carries it around
the semicircular parts of the housing to the outlet chamber,
whence the oil passes to the sight-feed glass and thence to the
engine.

37. In Fig. 13 is shown a section through the mechanical
lubricator used on the model 69 Overland car, in which six
individual pumps are used; the section shows one of these
pumps, which are plunger force pumps employing a single
valve. The pump consists of a cylindrical plunger a that
closely fits the pump cylinder 6, in the lower end of which there
is a delivery check-valve c that opens toward the engine and
is held to its seat by a small spring d. Two small holes e admit

Digitized by

Google

BEARINGS AND LUBRICATION

§10

oil to the pump cylinder when the plunger a is near the top of
its stroke. The plunger is actuated by an eccentric/ on a shaft g
that is rotated by the engine, and, in this case, carries six
eccentrics for driving the six pumps. A yoke h is attached to
the plunger a and passes through the cover i of the lubricator;

a spring ; holds the
yoke in contact with
the eccentric /, and,
as the eccentric re-
volves forces the plun-
ger downwards. The
upper end of the yoke
h is threaded and is
provided with an ad-
justment nut k and
locknut / by means of
which ^he quantity
of oil discharged is
regulated.

The action of the
ptunp is as follows:
When the pltmger a
is near the top of its
stroke, the holes e are
uncovered and oil
from the reservoir m
flows into, and fills,
the pimip cylinder 6.
As the eccentric re-
volves from the posi-
tion shown, the spring
; forces the pltmger a
downwards, thus closing the ports e. As the plunger continues
to descend, it pushes the oil in the pump cylinder ahead, there-
by opening the check- valve c and discharging the oil toward the
engine. As soon as the eccentric/ lifts the yoke h and plunger a,
the check-valve c is closed by the spring d and as soon as the
ports e are uncovered the cyUnder of the pump again fills with oil.

Digitized by

Google

§10

BEARINGS AND LUBRICATION

The delivery of oil is directly proportional to the distance
the plunger a travels; by screwing down the nuts k and / the
nut k comes in contact with the cover i before the eccentric /
has reached the lowest
point during its rotation,
and the travel of the
plunger is hence short-
ened and the oil delivery
reduced. Conversely, by
screwing the nuts k and I
upwards, the travel of
the plunger is lengthened
and the oil delivery is cor-
respondingly increased.

38. Plunger force
pumps with two valves
may or may not have an
adjustable stroke. That
used in the Studebaker
"35" engine, which has
a circulating constant-
level splash lubrication
system is of the non-
adjustable type; it is
shown in section in Fig.
14. It consists of a hori-
zontal cylinder a bored
to dosdy fit the plunger
fe, which is pushed in-
wards by an eccentric c
on the cam-shaft and
outwards by a spring d.
A ball check valve e is

Fig. 14

placed on the suction side of the pump and a similar check-
valve/ on the delivery side.

The action of the pump is as follows : On the outward stroke
of the plunger, the check-valve/ is closed and a partial vacuum

Digitized by

Google

80 BEARINGS AND LUBRICATION § 10

forms in the pttmp cylinder. In consequence, the atmospheric
pressure on the oil in the reservoir g forces oil up the suction
pipe joining the oil reservoir and the suction side of the pimip
cylinder; the oil lifts the suction check- valve e and fills the
pimip cylinder. The suction pipe is shown at e, Fig. 4. On the
next, or inwards, stroke of the pump plunger, the suction
valve e, Fig. 14, closes and the oil in the pump cylinder lifts the
delivery check-valve / and passes to its destination.

39. While the plunger pump described in Art. 38 is placed
in a horizontal position, the more common practice is to place
such ptmips vertically, and directly into the oil reservoir in the
bottom of the lower crank-case; the suction valve is then sub-
merged in oil at all times as long as there is any oil in the
reservoir, which insures a prompt action of the pimip as soon
as the engine starts. If a plunger ptmip is some distance above
the oil reservoir, the oil may leak out of the suction pipe; it
then becomes necessary to prime the pump in order to make it
pimip oil ; that is, the ptmip and suction pipe must be filled with
oil by hand.

40. An adjustable-stroke plunger ptmip of the vertical
type with two valves is used in the Northway, model 31, unit-
power plant, and is shown in Fig. 15, together with its
actuating mechanism. The plunger a is actuated by the
spring 6 in an upward direction, and is pushed downwards by the
follower rod c, which is pushed down by the eccentric d on the
shaft e. This shaft e carries a worm-wheel /, which engages
a worm g on the cam-shaft h of the engine, and hence is rotated
by the engine. In this particular case, the worm-wheel / and
worm g are so proportioned that twenty-five revolutions of the
cam-shaft produce one revolution of the shaft e, which means one
suction stroke and one delivery stroke of the plunger a. This
pltmger has an enlarged head, as shown, which bears at the
upper limit of the plunger travel against the adjusting screw i.
Screwing the adjusting screw down reduces the plunger travel
and hence the oil delivery; screwing the same screw upwards
increases the oil dehvery. The suction valve / is always sub-

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 81

merged in oil; the delivery valve k opens toward the passage /,
which in turn connects with the passage m from which the oil
passes through a pipe to a sight-feed glass and thence back to
the engine.

The ptrmp has an adjustable stroke because it is used with
a non-circulating constant-level splash lubrication system.

Pig. 16

The oil reservoir is filled through the filler pipe n, which is
placed in the center of the breather pipe o. The whole oil pump
is attached to the combined oil-pimip cover p and breather
pipe, and can be removed bodily for inspection by taking off
the cover p, which is bolted to the outside of the lower crank-
case.

Digitized by

Google

82 BEARINGS AND LUBRICATION § 10

41. A lifting oil pump is employed in the engine of the
Maxwell "25" car, and is shown in cross-section in Fig. 16.
The ptimp consists of a body a in which a cylindrical bucket b
moves up and down. This bucket is fitted
I at its lower end with an upwardly opening
ball check-valve c, which is prevented from
being lost out of the barrel by a cross-
pin d. An upwardly opening ball check-
valve e is also placed at the bottom of the
pump body a. The suction pipe / connects
to the bottom of the oil reservoir. The
pump bucket is driven from the forward
end of the cam-shaft by a crankpin g and
connecting-rod A, the crankpin g being
moimted ^ inch from the center on the
head i of the capscrew fastening the timing
gear to the cam-shaft, so that the bucket
has a stroke of f inch. On the upward
stroke of the bucket 6, the check-valve c
is seated, but the check-valve e is open,
and oil passes from the oil reservoir into
the pump. As soon as the downward
stroke of the bucket begins, the suction
check-valve e seats itself and the delivery
check-valve c opens, so' that the oil in the
Fig. 16 pump can pass to the inside of the plimger

and into the upper part of the pump body below the surface /.
On the next upward stroke, oil above the bucket is discharged,
flowing over the surface ;' to the timing gears of the engine.

OIL BELIEF VALVES

42. Forced-feed lubrication systems of the high-pressure
type fitted with a single pump are usually also fitted with an
oil relief valve. This serves not only as a safety valve and
prevents the breaking of any part in case the oil delivery pipes
should get blocked in some manner, but it also permits the
adjusting of the oil pressure so as to supply the correct amoimt
of oil to the engine.

Digitized by

Google

§10

BEARINGS AND LUBRICATION

The Mannon "32" car uses a high-pressure lubrication system
in its engines, some of which are fitted with the oil relief valve
shown in Fig. 17. In this system, an engine-driven gear-pump
takes oil, through the suction pipe a, from the reservoir in the
bottom of the lower crank-case and discharges it, from its
discharge chamber 6, through the discharge pipe c to the main
bearings. An opening at the top of the discharge chamber b
communicates with the suction side of the oil pimip; this
opening is normally closed by a ball valve d that is held to its

Fig. 17

seat by a helical spring e. The tension of the spring can be
changed by means of the adjusting screw/, which can be locked
by the locknut g. The pressure at which the ball valve d opens
depends on the tension of the spring e. As soon as the pressure
in the oil delivery pipes reaches that for which the relief valve
is set, the valve opens and lets oil escape back to the suction
side of the pump.

Some oil relief valves employ a poppet valve instead of a ball
valve.

OIL STRAINEBS

43. Practically all circulating constant-level splash oiling
sj^tems, pressure-feed oiling systems, and combinations of the
two systems that employ a pimip for circulating the oil, are
fitted with a fine-mesh wire strainer on the intake side of the

Digitized by

Google

84 BEARINGS AND LUBRICATION § 10

pump. This strainer is intended to remove metal particles
worn off the rubbing surfaces, carbon, and similar foreign
substances from the oil before it is delivered to the splash
troughs or bearings. Some manufacturers screen the oil
again after it leaves the pimip; an example of this is shown
at d, Fig. 10.

Oil strainers tased in connection with oil pumps are made in
different ways; as a general rule, they are easily removable
for inspection, cleaning, or replacement. One way in which this
may be accomplished is illustrated in Fig. 18, which shows the
motinting of the oil strainer on the suction side of the oil pimip-
of the Herce-Arrow oiling system that is shown in Fig. 10. The
strainer a, which is made of wire gauze and is cylindrical in

Fig. 18

form, is attached at one end to the removable plug b and at the
other end to the inlet pipe c of the oil pump. This inlet pipe
is perforated, is attached to the plug fe, and is loose in the inlet
passage to the pimip. Consequently, the plug b with the
strainer a and pipe c can be removed as a unit. Obviously, the
oil must be drained from the oil reservoir before the strainer is
removed.

Another way of making an oil strainer is shown at h, Fig. 14.
Sometimes an oil strainer forms part of the oil pump, and
is then exposed by removing the pump; an example of this con-
struction has been shown at r. Fig. 3.

44. To insure that only clean oil can enter the oil reservoir
of the engine-lubrication system, a number of ntianufacturers

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 86

place an oil strainer of fine-mesh wire gaiize in the filler opening
of the oil reservoir, which opening in many cases also serves
as the crank-case breather pipe.

OIL-LEVEL QAUOES

45. For the purpose of showing the height of the oil in
the oil reservoir of automobile engines, oil-level indicators,
which are often called oil gauges, are frequently fitted. Tliere
are four types of such indicators, which are gauge cocks, glass
oil gauges, float oil gauges, and transferring oil gauges,

46. Gauge cocks are cocks screwed into the oil reservoir
at different heights; an example of this method of finding the
oil level is given in Fig. 2, where gauge cocks are shown at e
and /. If oil does not come from the upper gauge cock but
comes from the lower cock when these cocks are opened in
succession, it shows that the oil level is above the level of the
lower cock but below the level of the upper cock.

47. Glass oil gauges were commonly used on cars in
which the oil reservoir was entirely separate from the engine;
sometimes they were incorporated in the reservoir, and occa-
sionally they were separate therefrom and moimted on the
dashboard. An example of the last-named practice is foimd
at g, Fig. 7. A glass oil-level gauge consists simply of a glass
tube partly enclosed in a metal shield for protection, the tube
being connected at the bottom to the bottom of the oil reservoir
and placed at the same level; the glass tube is open at the top,
generally through a small hole in the cap of the metal shield.
Glass oil gauges are rarely applied to oil reservoirs foimd in
the bottom of the lower crank-case, on accotint of the difiiculty
of observing their indication in that location, because the bottom
of the engine, when installed in the car, is generally enclosed
by a sod pan, and the gauge is too far down to be easily read
from the top when the hood enclosing the upper part of the
engine is lifted.

48. A float oil-level gauge is most commonly used. It
consists of a cork, or hollow metal, float that floats in a fairly

Digitized by

Google

86 BEARINGS AND LUBRICATION § 10

large vertical tube attached to the bottom of the oil reservoir.
A wire stem is attached to the upper end of the float, and the
end of the wire by its position on a graduated scale, or in a
glass tube, indicates thereon the oil level in the reservoir. The
object of attaching a long vertical stem to the float is to permit
readings to be taken at a level in plain sight
% \b of the observer. A float oil gauge is shown in
Fig. 4, where / is the float chamber and m the
glass tube. A cross-section of the float cham-
ber /, Fig. 4, is shown at t , Fig. 14, where the
float / and stem m are exposed to view.

49. A trajisferrlng oil gauge derives

its name from the fact that it indicates the

oil level in the oil reservoir by transferring a

column of oil from the reservoir to a higher

level vhere its height can be plainly seen.

This form of an oil gauge is attached to the

engine of the Hupmobile **32" car, and is

shown in Fig. 19. It consists of a cylindrical

tube o, the head b of which is screwed into a

vertical hole of the upper crank-case, and a

movable, closely fitting piston c attached to a

flat stem d. The tube o reaches down into the

oil reservoir; when the piston c is pushed to the

bottom it imcovers holes e through which oil

enters the tube and fills it to the same level

as exists in the reservoir. The flat stem d

passes through a rectangular slot in the head b

and is a rather loose fit therein; the stem is

graduated at the bottom, as shown, the figures

indicating in gallons the amount of oil that

i to bring the oil to the correct level in the reser-

le gauge, the stem is slowly pulled upwards; the

otion closes the holes e and the oil in the tube

As soon as oil appears at the slot in the head 6,

on the stem is read at the level of the upper

eadft.

Digitized by

Google

§10

BEARINGS AND LUBRICATION

This particular oil gatige differs from other forms in that it
does not show how much oil is in the reservoir, but how much
is to be added to the reservoir. A gauge of this kind can be
graduated, however, to show the depth of oil in the reservoir.

OIL SIOHT-FEED GLASSES

50. The great majority of constant-level splash lubrica-
tion systems that employ an oil pump or oil pimips are pro-
vided with a device placed where it is easily observed by the
driver, and which shows whether the ptimp or pumps are work-
ing properly. This device is spoken of as an oil sight-feed glass;

Fig. 20

it derives its name rrom the fact that it permits the stream of
oil coming from the pump or pimips to be observed through a
glass window or a glass tube.

Fig. 20 shows an oil sight-feed glass in which the oil is observed
through a circular glass window, or bull's eye, a. This device
consists of a brass body b circular in cross-section and provided
with an oil inlet c and oil outlet d. A pipe is connected from
the delivery side of the oil pimip to the oil inlet c; a much
larger pipe is connected to the oil outlet d and conveys the oil
tQ the engine. The oil inlet c connects with a downwardly
pointing nozzle e. The glass window o is set into a ring /
that is screwed to the body, as shown.

Digitized by

Google

88 BEARINGS AND LUBRICATION § 10

In a circulating constant-level splash oiling system, the
proper working of the oil pump is indicated by a continual
stream of oil issuing downwards from the nozzle e\ in a non-
circulating constant-level splash oiling system an inter-
mittent stream issues from the nozzle e.

The oil outlet d is made much larger than the oil inlet c
in order that the oil may flow away freely to the engine; the
inflow of oil is positive, while the outflow is only imder the
influence of gravity.

51. Oil sight-feed glasses in which the flow of oil is observed
through a glass tube do not differ in principle from the one
described in Art. 50. As a general rule, the oil inlet and oil
outlet are at the same level ; the oil inlet is fitted with a vertical
tube bent downwards on top and pointing toward the outlet
opening. A glass tube surroimds the vertical tube and is
closed on top by a metal cap. Such a sight-feed glass is shown
at A, Fig. 4, and at n. Fig. 14.

Forced-feed lubrication systems of the high-pressure type
are not fitted .with oil sight-feed glasses but with pressure
gauges.

OIL AND GREASE CUPS

52. On unimportant movable joints that require oil only
occasionally, oil cups are used to some extent. An oil cup,
as used in automobile work, is not a device that holds a quantity
of oil that is gradually fed out, but is a quickly opened covering
of suitable form applied to the outer end of an oil hole; it
permits the ready introduction of the spout of an oil can and is
readily closed to keep dirt out of the oil hole.

Three common forms of oil cups are shown in Fig. 21. All
three are threaded at their lower end to permit their being
attached to the oil hole to which they are applied. The one
shown in (a) has a nurled sleeve o with an oblong hole h\ the
sleeve a can be turned so that its hole 6 registers with a similar
hole in the hollow stationary body c of the oil cup. When -the
two holes register, oil is introduced with an oil can; after this
has been done the sleeve a is supposed to be turned tmtil the

Digitized by

Google

§ 10 BEARINGS AND LUBRICATION 89

hole in the body is covered by the sleeve, thus keeping out dirt.
The oil cup shown in (6) has a cover a attached to a spring b
fastened to the body c of the cup. To open the cup, the cover
is puUed into the position shown; after the oil has been intro-
duced the cover snaps back on the body when released, thus
closing the cup. The oil cup shown in (c) has a central hollow
sleeve a that when pulled up against the resistance of a helical
spring inside of it, exposes the hole fe, through which oil can be
introduced. As soon as the sleeve o is released, the spring
pulls down the sleeve until its head is in contact with the upper
edge of the body c, thereby closing the cup.

53. Greajse cups are receptacles for grease that are
applied to various important joints requiring grease lubrication.

(»> (b) (e)

Fig. 21

such as the various steering-knuckle pins, spring-shackle bolts,
etc., and are so constructed that the grease they contain is easily
forced out of them to the bearing to be lubricated. There
are two kinds of grease cups in use, known as plain grease cup^
and automatic grease cups. Plain grease cups are used for the
intermittent feeding of grease; automatic grease cups are used
for continuously feeding grease, but are not regularly employed
in automobile work.

54. A very simple plain grease cup extensively used on
automobiles is shown in Fig. 22. The cap a is imscrewed from
the body 6, nearly filled with a suitable grease, and screwed
on again to about the position shown in the figure. The body b

Digitized by

Google

90 BEARINGS AND LUBRICATION § 10

is permanently screwed into a hole that runs to the bearing
surfaces. The pressure of the cap a upon the grease is suiBdent
to feed the grease to the bearing. The cap should be given
a turn or two each time the automobile has run a certain
distance. When the
cap is screwed down as
far as it will go, it should
be removed, refilled,
and replaced.

The plain grease cup
shown in Fig. 23 has at
b a packing of leather
or other suitable mate-
Fic.22 rial that is held in posi- j^^ ^3

tion by the threaded
piece a, which should be tight enough to make the packing fit
dose to the cap thread. Dust is less liable to enter this cup than
the one shown in Fig. 22; also, its cap is less liable to jar loose.
In Fig. 24 a ratchet grease cup is shown. It is provided
with a bottom piece o that cannot rotate, but can move up and
down. The spring b presses the piece a up against the lower
edge of the cap d,. and when the projection c corresponds with
the notch in the lower edge of the cap,
the latter is usually
held so tight that
it will not be im-
screwed by vibra-
tion; neverthdess,
it can be readily
turned by hand.
This grease cup is
suitable for use on
moving or jarring
Pig- 24 paj^s of an auto- ^g-25

mobile, as the construction tends to prevent the imscrewing
and loss of the cap.

In another widely used form of a ratchet grease cup, which is
shown in Fig. 25, the piece a pressed upwards against the lower

Digitized by

Google

1 10 BEARINGS AND LUBRICATIO^

edge of the cap b has two projections resembling
the cap has two notches to fit these projections,
jections slant in such a direction that the cap
down easily, but cannot be turned up unless
first pressed out of engagement with the edge
With this construction, it is practically impossil
to unscrew tmder vibration.

55. While most plain grease cups force the g
ing down the cap, as for instance those shown in
there is another kind used to some extent, one
is shown in Fig. 26, in which a piston is placed
on top of grease contained in the cylindrical
solid body a of the cup. A threaded stem b
attached to the piston passes through a threaded
hole in the removable grease-cup cover c, and is
fitted with a handle d by means of which the
stem can be turned, and hence the piston can
be moved in or out. To fill the cup, the cover c
is unscrewed and the piston puUed out of the
body a.

Grease cups are made of polished, nickel-pl
brass, or of steel. The threads on the shan
standard iron-pipe threads, varying in size froi
Grease cups of large size with shanks thread
i-inch pipe thread are on the market but are hi
in automobile work; in fact, grease cups with
than J-inch pipe thread are quite rare. The caj
cups used in automobile work ranges from f ov
of grease, generally speaking.

Digitized by

Google

Digitized by

Google

AUTOMOBILE TIRES

(PART 1)

TIRE CONSTRUCTION AND APPLICATION

TYPES OF TIRES ANB RIMS

PNEUMATIC TIRES

1. Introduction. — ^As the name implies, the pneirmatio

tire consists of a hollow combination rubber-and-fabric
exterior filled with air tmder pressttre. It is particularly adapted
to the pleasure automobile because of its resiliency, which
enables it to absorb the shocks caused by the tmevenness of the
road surface. No material has as yet been discovered that will
satisfactorily take the place of the rubber tire containing com-
pressed air, and hence practically all pleasure cars are
equipped with pneumatic tires. Solid tires, made of rubber
and solid in structure, are used on motor buggies and on nearly
all commercial vehicles, where ease of riding is not of prime
importance. Another form of tire, known as the cusMon tire,
has been xised to a limited extent. It is made of fairly soft
rubber in a variety of shapes intended to give a cushion effect.
Pneumatic tires are divided into two subclasses; namely,
single-tube tires and double-tube tires.

2. Single-Tube Tires. — Single-tube tires resemble an
endless ring of ordinary rubber hose, the inside being filled with
air under pressure. While widely used on automobile wheels in

COPYIIiaHTBO BY INTBRNATIONAI. TEXTBOOK COMPANY. ALL MOHTS RBSBRVKO

§11

222B— 45

Digitized by

Google

2 AUTOMOBILE TIRES § 11

the early days of the automobile industry, their inherent defects
have caused a gradual passing away, until single-tube tires are
not used on modem automobiles.

A cross-section of a single-tube pneumatic tire in place on the
wheel rim is shown in Fig. 1. The tire a is made up of
several layers, or plies, of cotton or linen fabric of very open
weave embedded in the rubber. The latter forms the air-
tight, waterproof portion, and, externally, the wearing surface
of the tire. The fabric is shown in four concentric dotted circles
in the figure. For mechanically fastening the tire to the wheel

rim 6, a number of tire
lugs c are provided.
These lugs project
through the wheel rim
and are tapped to receive
a lug screw d, which
holds in place a damp e
that bears against the
wheel rim and holds the
tire in place.

Instead of using the
method of fastening just
described, some makers
of single-tube tires use
studs that are perma-
nently fastened to the
lugs; these are then
wholly inside the tire, and the tire is fastened to the rim by
means of clamps and nuts attached to the studs. Single-tube
tires thus attached are intended for use on wire wheels, and
cannot be readily used on artillery wheels. Single-tube tires
made to be attached as shown in Fig. 1 can be applied to either
wire wheels or artillery wheels, provided screws of sufficient
length are used.
Single-tube tires are made with either five or eight tire lugs.

3. Classification of Double-Tube Tires. — ^The form
of pneumatic tire that is commonly used on pleasure cars is the

Digitized by

Google

§ 11 AUTOMOBILE TIRES 3

double-tube tire. This tire consists of two parts; namely, an
outer part composed of rubber and fabric, and called a casing,
or shoe, and an inner part in the form of a hollow cylindrical
ring made of soft rubber, and called an inner tube, or simply a
tube.

Double-tube pneumatic tires may be divided into three tjrpes
in accordance with the manner in which they are fastened to
the rim of the wheel. Thus classified, the three types are the
regular clincher tire, the mechanically fastened tire, and the
quick-detachable tire,

4. Regrular cllnclier tires are tires that are fastened to
a one-piece rim chiefly by the pressure of the contained air,
sometimes aided by a few special clamps.

Medianically fa,stened tires are tires that are held to
the rim by mechanical means.

Qoick-detacliable tires are tires that are held in place by
specially constructed rims and are put on or removed by first
removing the detachable portion of the rim. They are made
in two forms; namely, the quick-detachable clincher tire and the
quick-detachable straight-side tire, also known as the Dunlop tire.

5. Resrular Clincher Tires. — ^The oldest form of double-
tube tire is the regrular clinclier type, which is made to
fit one-piece clincher rims. The tire is held in place chiefly by
beads that fit snugly in place under the clincher, or bent-up
portion, of the rim. The beads on a regular clincher tire are
soft; that is, they are made of rubber and fabric only, so as to
be flexible enough to slip over the rim flange. On the larger
tires of this type, tire lugs, or clamps, are used to aid in holding
the tire on the rim.

6. In Fig. 2 is shown a short section of a double-tube
pneumatic tire of the regular clincher type in place on the wheel
rim. The casing, or shoe, a of the tire, instead of being com-
pletely tubular, is open along the side next to the rim 6. The
middle of the rim is nearly flat and the edges are ciuved inwards
toward each other, as at c, so as to form a clinch on each side
for holding the tire casing in place. The casing is formed
with beads d that fit into the clinches of the rim. An inner

Digitized by

Google

4 AUTOMOBILE TIRES § 11

tube e of soft elastic rubber is placed inside the casing. This
inner tube retains the air in the tire. It is provided with a valve
through which air can be forced into the tube by means of a
pump or some other device, an^ the valve can be opened to
allow the escape of air from the tube when it is to be deflated.
This air valve is not shown in Fig. 2. The pressure of the com-
pressed air forces the beads of the casing into the clinches of

the rim and retains them
there so that the tire is held
in place when fully inflated.
In order to secure the tire
more firmly to the rim, that
is, so that it will not be
thrown out when a side pres-
sure is exerted upon it, as
when a car is turning a curve
at high speed, devices vari-
ously called tire lugs, clamps,
clips, or security bolts, of
which the head of one is
partly shown at/, are pro-
vided. The head / of the
tire lug is shaped to conform
to that part of the casing
with which it is in contact.
^^'^ A bolt extends from the

head of the lug inwards toward the center of the wheel, and is
threaded to receive a nut g, which is used to draw the head of
the clamp down tight against the inside of the casing. In the
smaller tire sizes in which the regular clincher tire is usually
made, tire lugs are generally dispensed with and the bead alone
is depended on to hold the tire in place.

The thickest portion h of the tire is called the tread. It is the
part that comes in contact with the roadway when the tire is in
use. One or two strips of fabric, called breaker strips, are gener-
ally placed between the tread and the main portion of the fabric.
These strips strengthen the casing, and in case of great wear
become exposed and thus indicate the necessity of repair.

Digitized by

Google

§ 11 AUTOMOBILE TIRES 6

When an ordinary clincher tire of the form just described
is being placed upon the wheel rim or removed from it, the
beads of the tire must be lifted over the clifacher portion of the
rim. The outside diameter of the clinch is larger, of course,
than the inside diameter of the bead of the casing. The bead
must therefore be elastic enough to stretch sufficiently to pass
over the clinch. In the tire shown in Fig. 2, each bead has a
rubber filling that is elastic enough to allow the tire to expand,
as just described.

7. Meclianlcally Fastened Tires. — ^The Fisk bolted-on
tire, a short section of which is shown in Fig. 3, is an example
of a mechanically fastened

double-tube pneumatic tire.

The rim a of the wheel is made

of a flat strip of steel. The part

of the tire casing in contact with

the rim is also made flat. Two

retaining rings fc, held in place

by means of bolts that extend

from side to side through the

tire just outside the wheel rim,

are provided to hold the tire in

place. The head of one of the ^

bolts is shown at c, and the nut

on it at d. The head fits over

the side of the wheel rim a and

retaining ring 6, and a clamp e ^^^' ^

just under the nut d fits the wheel rim and ring on the opposite

side. The tire casing is split circumferentially at / in a plane

perpendicular to the axis of the wheel.

8. Quick-Detachable Cllnclier Tires. — ^The standard
form of double-tube tire, which is used much more extensively
than the regular soft bead clincher type, is the quick-detach-
able clincher tire. The only difference between this form of
tire and the regular clincher type is in the construction of the
bead. In the quick-detachable type, the bead is made stiff and
inextensible, and the tire is put on, or removed from, the rim

Digitized by

Google

6 AUTOMOBILE TIRES § 11

by removing a detachable ring that forms one of the clinches,
instead of by stretching the bead over the edge of the clinch.

9. A short piece of a quick-detachable clincher tire, in place
on one form of a Firestone quick-detachable rim, is shown in
Fig. 4. The beads a, which are much stiffer than in the regular
clincher tire, fit into two clinches b and c that hold the tire in
place. The one clinch 6 is an integral part of the rim, but the
other clinch c is a solid ring that is detachable. The retaining
ring c can be removed by pressing it in toward the center of the
rim after the tire has been deflated, and then removing the split
ring d from the groove of the wheel rim into which it fits. The
split ring can be pried out of the groove by a screwdriver, or

similar tool, placed in a

notch e cut in the side of

the wheel rim . The ring d

is prevented from sliding

around the rim by a pin /

that is attached rigidly to

the ring and that fits in a

second notch in the rim.

After removing the rings c

and d, the complete tire

can be slipped off side-

^^' ^ wise from the wheel rim.

When being removed, the tire should first be taken off at the

side opposite the air valve.

A loose protective flap g in the shape of a channel ring is
furnished by some tire makers. This flap is placed between
the edges of the casing to form a close joint and a smooth sur-
face for the inner tube to bear against. The flap is generally
made of rubber strengthened by embedded woven fabric. A
breaker strip h is placed on the inside of the tread of the tire
to strengthen it. No tire lugs, or clamps, are required for a tire
of this type.

10. In connection with quick-detachable clincher tires,
it is to be noted that such a tire cannot be applied to a regular
one-piece clincher rim. A regular clincher tire can be applied

Digitized by

Google

§ 11 / AUTOMOBILE TIRES 7

to a rim designed for a quick-detachable clincher tire of the same
size, but it is not advisable to do this becatise quick-detachable
clincher rims are usually not drilled for tire lugs, or security
bolts, and hence the tire is liable to be torn off the rim while
rounding comers if it is not fully inflated.

11. Quick-Detachable Straight-Side Tires. — One of

the first quick-detachable tires to be placed on the market, and
one that is quite extensively used, is the quick-detachable
straight-side tire, or Dunlop tire, A section of such a tire
mounted on the wheel rim is shown in Fig. 6. This tire is not
provided with beads, as are the regular clincher and quick-
detachable clincher tires, but is built with straight sides and
is held in place by solid re-
taining rings a that con-
form in shape to the sides
of the tire. In order to
prevent the inner edges of
the straight-side casing
from expanding apprecia-
bly in diameter when the
tire is inflated, endless
wires b are embedded in
the hard-rubber base.
These wires form a ring ^^'^

that will not expand, and hence a tire of this kind cannot be
put on or removed over a clinch. A quick-detachable straight-
side tire is removed in the same manner as a quick-detachable
clincher tire.

An ordinary quick-detachable clincher tire can be used on a
rim of the type shown in Fig. 5 by simply reversing the rings a,
thus forming clinches.

12. Detachable-Tread Tire. — In order to provide means
for readily replacing the worn tread of a pneumatic tire, a type
of tire in which the casing is made up of two distinct and separate
parts has been designed. An example of such a tire is the Good-
year detachable-tread tire, the two-part casing of which is shown
in Fig. 6. This casing is made up of the tread a and the car-

Digitized by

Google

8 AUTOMOBILE TIRES § 11

cass by which is the fabric portion of the tire. In view (a) the
tread is shown in place on the carcass, and in view (b) it
is shown removed.

The detachable tread a is of regulation thickness and in
addition has two plies of fabric c at the base. It is held in place,
when assembled, as shown in (a), simply by the friction between
the two parts resulting from the pressure of the air in the tire.
The sides of the tread are provided with two non-stretchable
beads d, which hold it snugly to the sides of the carcass. Instead
of being made exactly roimd to fit the carcass perfectly, the

Fig.

inside of the tread is made slightly flat on top so as to form two
air chambers e and /, one on each side of the point where the
tread comes in contact with the road surface. It has been
f oimd from experience that this construction prevents a certain
amount of wear that would otherwise be caused by the friction
between the two parts.

13. With the detachable-tread tire, if either part becomes
worn it can be replaced without buying a complete casing.
The carcass is held to the rim in the usual manner; the one
shown in Fig. 6 is of the quick-detachable straight-side type.

Digitized by

Google

§ 11 AUTOMOBILE TIRES

DEMOUNTABLE AND QUICK-DETACHABLE BIMB

14. Explanation of Terms. — ^A rim so constructed that
it can be easily removed from the wheel, thus affording a ready-
means for changing tires on the road, is called a demountable
rim. By having the rim demoimtable, a complete spare tire
can be carried inflated on an extra rim, so that the arduous work
of changing the tire on the rim on the road and inflating it is
eliminated. If the demoimtable rim and its fastenings are of
proper form and in good condition, they can be quickly removed;
an inflated spare tire with its rim can then be substituted in
much less time than is

ordinarily required for
putting on a tire, together
with its inner tube, and
then inflating it.

A quick-detachable rim
is one that permits the
removal of the tire from
its rim without the
physical effort required
to stretch it over a clinch,
as in the regular clincher
type.

A quick-detachable de-
mountable rim is a de-
moimtable rim that is ^'^'^
fitted with some form of quick-detachable device. With this
type of rim, the rim and tire can first be removed from the
wheel, after which the tire can readily be removed from the rim
by means of the quick-detachable appliance, or the tire can be
removed without removing the entire rim.

15. Types of Demountable Rims. — ^Various methods
for securing demountable rims to the felloe of the wheel, so that
they can be readily detached, have been devised. A form of
demountable rim that is widely used is that shown in Fig. 7,
which shows a short section of one form of the Firestone quick-

Digitized by

Google

10 AUTOMOBILE TIRES § 11

detachable demotintable rim. The rim a is held in place by a
wedge-shaped clamping ring b that fits between the beveled
edge of the rim and the beveled edge of the felloe band c. This
ring, and consequently the rim, can be removed by removing

six rim clamps d, which
are held in place by
hexagonal nuts on bolts ^
" having specially shaped
heads.

16. A cross-section
of the Stanweld de-
mountable rim ntunber
^'^•^ 40, which is similar in

principle to the Firestone, is shown in Fig. 8. An adjusting
ring a, having two beveled surfaces, is held in place by six
clamps 6. The clamp bolts c extend through the felloe and butt
against the felloe band d by
means of specially shaped heads.
The clamps b are supported by
the clamp-bolt nuts e in such a
manner that they are free to ad-
just themselves to position at all
times. The adjusting ring a is a
band of spring steel and is trans-
versely split. It is easily removed
or applied with the hands when
the clamps are unlocked.

17. An example of a bolted-
on demountable rim is shown in
Fig. 9, which is a sectional view
of the Baker bolted-on rim ap-
plied to a tire. A felloe band a is
shrunk on the wooden felloe b

of the wheel and the rim c is held in place by six bolts d that
support the same ntmiber of wedges e. The nuts / are fixed in
the felloe and the bolts are screwed into them when the rim is
assembled. A sleeve g forces the wedge e out when the bolt

Digitized by

Google

§ 11 AUTOMOBILE TIRES 11

is unscrewed. The sleeve is crimped into a groove in the bolt.
The rim c has integral clinches like a regular clincher rim, but
it is split transversely so that the circumference can be reduced
when the tire is put on or taken off. When assembled, the ends
of the rim are bound together by means of an anchor plate and
four stud bolts.

18. Fig. 10 shows the construction of the Booth demoimt-
able rim, which differs from the more common forms previously
described in that a special locking device is used. Three of the
locking devices are arranged at equal intervals around the
channel-shaped wheel

rim a. By means of
these devices, the
cleats 6, which are at-
tached to the de-
mountable rim c, may
be locked in place on
the solid rim a, thus
holding the demotmt-
able rim c on the
wheel.

19. The locking
device used on the
Booth demountable
rim is shown in detail

in Fig. 11 in both the ^^- ^^

unlocked and the locked positions. When in the unlocked
position, as shown in view (a), the cleats a are free to be slid
off of the wheel rim 6, and, therefore, the demoimtable rim
and tire can be removed. The demoimtable rim is locked in
place on the wheel rim b by turning a worm-screw c, which
meshes with two worm-gears d that in turn engage with pro-
jections on the cleats a. Turning the screw c in a right-handed
direction revolves the gears d in such a way as to draw the
cleats a on the rim b and lock the demountable rim in posi-
tion, as shown in view (6). This device, being a worm-and-gear
combination, is self -locking.

Digitized by

Google

12 AUTOMOBILE TIRES §11

20. Demountable rims varying somewhat in design from
those just described are also tised, but the most common types
are those that make use of bolts, as shown in Figs. 7, 8, and 9.
As a general thing the method of removing a demountable rim
is comparatively simple, so that it can usually be ascertained
upon a brief examination.

21« Forms of Qiiick-Detacliable Locking Devices.

Several forms of quick-detachable mountings for tires are used,

each with its distinctive
method of removal and
replacement. A com-
mon form of rim is
that in which the inner
retaining ring is secured
in place by means of a
locking ring, as shown
in Figs. 4 and 5. In
some rims of this type,
the locking ring is made
with an L-shaped cross-
section, but it is applied
in the same manner as
the one referred to.

22« Another com-
mon form of <juick-de-
tachable rim is that in
which a single side ring
may be expanded and
removed without the use of a locking ring, an example of which
is the Stanweld rim shown in Fig. 8. Two detailed views of the
locking device used on this rim are shown in Fig. 12. The outer
side ring a of the rim is split transversely, and on either end is
an L-shaped lug b that projects through a slot made in the bot-
tom of the groove into which the ring locks. The lock consists
of a cam c operated by a lever, both being fastened to the rim
base d. When the side ring is locked, as shown in view (a),
the wide portions of the cam c extend into the slots of both

^»> Pig. ir (^)

Digitized by

Google

§11

AUTOMOBILE TIRES

lugs b that are on the ends of the ring. When in the locked
position, the cam-lever is held in place by means of a small pro-
jection on the lever that catches in a corresponding depression
in the rim base.

The lock is disen-
gaged by inserting a
screwdriver between
the cam-lever and the
rim base and swing-
ing the lever out until
the cam is released
from the lugs, as
shown in view (6). A
slot e in the lever al-
lows the screw driver
to be easfly engaged
with it dining this
operation. The side
ring a is removed by inserting a screwdriver in a slot/ and
prying the ring off over the edge of the rim, when it can be taken
off with the hands.

23. In the Standard Universal rim, a removable side ring like
that shown in Fig. 12 is used, but it is held in place by means of
a T bolt and cap instead of by a special latch as on the Stanweld.
The head of the bolt extends into the slots in the lugs, and the cap,

through which the
bolt extends, is fitted
over the two lugs,
thus clamping the
whole together when
the nut is applied to
the end of the bolt.
The tire is detached

by removing the nut, cap, and T bolt; and prying the ring from

the groove in the rim.

24. Transversely Split Rims. — In order to facilitate
the removal of the tire, some demoimtable rims are split trans-

PlG. 13

Digitized by

Google

14 AUTOMOBILE TIRES §11

versdy instead of being fitted with a quick-detachable device.
A rim of this type can be sprung together after it has been
demoimted and the tire can then be removed or put on.

The ends of transversely spht rims are locked together in a
variety of ways. In the Booth split rim a taper pin is used, as
shown in Fig. 13. When moimted on the wheel, the ends of the
rim are held together by a taper pin a that passes through

brackets b on the ends of
the rim. The tire is re-
moved by first demounting
the rim and then taking
out the taper pin. The one
end of the rim can then be
pressed down and sidewise,
thus contracting its cir-
cumference and permitting
the tire to be detached.

25. The Baker bolted-

on demountable rim makes

use of an anchor plate for

locking the ends of the rim

in position, as shown in

Fig. 14. The rim is split

diagonally at the valve

stem and the ends are held

together by a plate a, which

fits over four studs carried by the rim. A fifth hole in the plate

allows the valve stem to pass through. The tire may be

removed after the rim has been demoimted, by taking off the

anchor plate and bringing the two short sides of the rim together,

thus reducing its circumference.

Digitized by

Google

§11

AUTOMOBILE TIRES

26. A different form of locking device for a transversely split
rim is shown in Fig. 15, which shows the device applied to the
Detroit demountable rim. A latch, or cross-tree, a is used to
lock the ends of the rim in place, as shown in view (a), in which
view the demountable rim b with the tire c is in position to be
placed on the wheel rim d. When locked, the latch a engages
with two buttons on the inside of the rim. The openings for
the buttons are cut
at an angle so that
as the latch is turned
to be locked in place,
the rim is expanded.
Dirt and water are
prevented from en-
tering the tire casing
by a small filler seg-
ment e that is se-
cured to the locking
cross-tree. When
assembled, the tire-
valve stem extends
through the center
of the latch and the
filler segment. A
detail of the latch
and segment is
shown in view (b).

The demountable
rim is prevented
from slipping around
the wheel rim by blocks / and g that engage with each other
when the rims are assembled. An expanding tool that is fur-
nished with the rim may be used for expanding the rim to
remove the filler segment if it should become rusted.

27. Clrcumferentlally Split Rims. — ^An example of a
demountable rim that is split ciramiferentially is the Stanweld
rim, number 30, which is shown in Fig. 16. The sections of the

Fig. 16

Digitized by

Google

16 . AUTOMOBILE TIRES § 11

rim are shown in detail in view (a). The base of the rim is in
two sections a and b that can be locked together by two semi-
circular locking rings c and d, which are shown tied together in
order to show their construction. Each section of the rim has
a series of lugs that can be made to engage with the slots in the
locking rings and hold the rim together. One end of each lock-
ing ring is securely riveted to the wide section a and the free
ends may be locked by means of a swinging latch when assem-
bled, as shown in view (fc), in which the various parts are
lettered the same as in view (a). The latch consists of the
main latch e and a cam-latch/ that is used for locking in place
the main latch.

The tire is removed from the rim by first opening the cam-
latch / and then the rim latch e with a screwdriver, small
ptmch, or similar tool, and prying the locking rings from the
lugs, beginning at the free ends and working toward the riveted
ends. The two sections of the rim can then be removed, one
at a time. When locking the rim, the reverse operation is gone
through.

Ant VALVES, LUGS, AND INNEB TUBES

28. Tire Air Valves. — In the United States, the kind
of check-valve in tmiversal tise for admitting air under pressure
to a single-tube automobile tire or inner tube and retaining it
therein, is that known commercially as the Sclirader valve.
The one made for inner tubes is illustrated partly in section in
Fig. 17 (a). In (b) the air check, which is known commercially
as the valve insides, is shown to an enlarged scale.

Referring to view (a) , the stem head a is placed inside the inner
tube, and a metal washer b is clamped down against the tube
by means of the nut c, which fits on the threaded body of the
hollow stem d. Between b and c is a guard, or spreader, e, called
the bridge clip, that prevents the inner tube from coming into
contact with the nut c. This guard also fits against the side
of the shoe, so as to make a tight joint for the bearing surface
of the inflated inner tube. The stem d is flattened on two
opposite sides, as shown at /, so that it can be held with a
wrench to prevent its twisting around while tightening the nuts.

Digitized by

Google

§11

AUTOMOBILE TIRES

The nut g, when tightened, presses the leather washer h against
the felloe. The end ; of the hole i is threaded to receive the
valve insides.

The outside of the valve stem receives a small cap k, which
protects the valve from dust and other foreign matter. At the
same time, loss of air from the inner tube, in case the air check-
valve should leak, is prevented by the rubber packing disk, or
washer, /, which bears against the end of the valve stem when
the cap is screwed in place.
A large dust cap m screws
over the larger portion of
the stem against a leather
washer «, and thus forms a
protection for the entire
end of the stem.

29. When the threaded
piece o is screwed down to
the proper position, as
shown in Fig. 17 (a), the
conical rubber packing
ring p, view (6), presses
against a corresponding
coned surface in the hole
through the stem, making
an air-tight joint. At the
same time, a thin brass cup-
shaped piece q bears against
a square shoulder farther
down in the hole, so as
to compress the coiled expansion spring r, and thus force
the valve s up toward the valve seat t. The valve 5 is pro-
vided with a soft-rubber valve disk u, against which the com-
paratively sharp edge of the valve seat t bears when the valve
is closed. When air is passing through the valve into the inner
tube of the tire, the valve 5, together with its rubber disk m, is
forced away from the valve seat t by the pressure of the air
against the valve disk.

222B— 46

(^)

Pig. 17

Digitized by

Google

18 AUTOMOBILE TIRES § 11

When it is desired to allow the air to escape, the valve can
be opened against the pressure of the air in the inflated tube
by pressing against the end of the solid stem v. The only
part rigidly attached to this stem is the valve s, so that when
the stem v is pushed in against the coiled spring r , the valve s
is forced away from the valve seat t. As soon as the valve
and seat are separated, the air can escape.

30« In order to provide a ready means of screwing the
valve into place and removing it, the small cap k has a slot w
across an extension of its outer end and the end of the part o
is cut away so as to leave projections Xy over which the slot w
fits. The two parts together thus operate as a screwdriver

Pig. 18 ^^

and a slotted screw head. The stem-like extension of the
cap k, across which the slot w is cut, fits loosely into the end
of the valve stem, and can therefore be readily inserted to
screw the valve into place. The rubber packing / in the
small cap has a depression on the side next to the valve, in
order to prevent it from striking the end of the small stem v
in case the latter happens to project beyond the end of the
main valve stem d. The rubber packing is correspondingly
crowned on the side opposite the depression so as to secure
sufficient thickness of material. The small solid valve stem
is flattened at both ends so that the parts of the valve will
not fall apart when removed from the main valve stem.

On examining a leaky air valve, it is sometimes fotmd that
the leak is due to the packing ring p being put on incorrectly

Digitized by

Google

§ 11 AUTOMOBILE TIRES 19

when the valve insides* were assembled. The obvious remedy
of this is to remove the ring and replace it so that its conical
surface coincides with the surface of the valve seat /.

Schrader valves are made with different lengths of stems to
suit different sizes of inner tubes and thicknesses of wheel felloes.

31. Tire liogs. — ^Two forms of devices for fastening
an ordinary, or regular, clincher tire on the wheel rim are
illustrated in Fig. 18. The lug shown in view (a) has a rubber-
covered head, or spreader, a, inside of which is a piece of metal
formed to a suitable shape, and to which is attached the threaded
stem b. The nut c is made cap-shaped to protect the stem.
A leather washer is usually placed between the nut and the
felloe of the wheel, in order both to make a tight joint and to
reduce the liability of the nut to work loose.

In view (6), the head a, which fits inside the shoe between
it and the inner tube, is covered with canvas on the side that
comes against the shoe and with leather on the other side.
The metal portion of the head lies between the leather and
the canvas. The stem b has the same form as the stem of
the lug just described and passes completely through the
nut c, A locknut d is also placed on the stem, and it is screwed
down against the nut c in order to lock this nut in place after it
has been sufficiently tightened. The locknut d is cap-shaped
and is closed at the end to protect the stem.

In order to eliminate the necessity of using a wrench for
tightening the tire lugs, a wing nut, or thiunb nut, is sometimes
used on lug stems.

32. The head of a tire lug, clip, or clamp must be of such
form as to fit closely and smoothly against the inside of the
tire casing. It should also fit against the wheel rim in the
same manner when the latter is not completely covered by
the casing; otherwise, a hole will be blown through the inner
tube or the tubes will be locally stretched and permanently
distorted around the head of the lug. The excessive local
stretching will weaken the rubber and ultimately will likely
cause a hole, which may not occur, however, until the tube
has been removed, put in a casing, and inflated again.

Digitized by

Google

AUTOMOBILE TIRES

§11

Tire clamps, or lugs, are usually omitted on regular clincher
tires of the smaller sizes, say up to and including 3i inches
diameter of cross-section, in which case the friction of the bead
in the rim is depended on to keep the tire from creeping around
the rim. The tires seem to be very effectively held in this man-
ner as long as they are fully inflated. However, if the tire on a
rear wheel is run after it has become partly deflated, it is liable
to creep aroimd on the rim. When this creeping occurs, there
is danger of shearing or of tearing the valve from the inner tube.

If tire clamps are not
used on a rim that has
holes for them, the holes
should be tightly
plugged. The plugs used
for this purpose must be
smoothed down flush
with the rim where the
tire bears against it.

Tire clamps serve to
prevent the shoe from
being pulled from the
rim when turning curves,
and also to prevent it
from creeping around on
the rim. The results of leaving clamps off seem to indicate
that they are not actually necessary except when the tire
becomes deflated.

Pig. 19

33. Bridge Clips. — Several forms of bridge clips are used
with Schrader valves in order to protect the inner tube at the
point where the valve stem is attached, and also to prevent
creeping of the tire on the rim. The clip is a large, specially
shaped washer, resembling the head of a tire lug, that surrounds
the valve stem close to the inner tube, as shown at e in Fig.
17 (a). A detailed view of this clip is shown in Fig. 19 (a).
This is a very common form of bridge clip. A much larger dip
than this is the Michelin bridge clip shown in view (6). It is
shaped to conform approximately to the shape of the inner tube

Digitized by

Google

§ 11 AUTOMOBILE TIRES 21

and is provided with short projections along each side that tend
to prevent it from slipping around the tire and thus to relieve
the valve stem of a certain amoimt of strain.

Another form of bridge clip, applied to an inner tube, is shown
in Fig. 20. The metal clip a is supported by a nut b on the valve
stem and a metal washer next to the tube. The inner tube
is reinforced at this point by an additional thickness of rubber
that is cemented on.

A clip made up like the tire-lug head shown in Fig. 18 (a) is
largely used. Any
form of bridge clip can
be used on any type
of double-tube tire,
although • some tire
companies recommend
special clips for differ-
ent types of tires.
For instance, the Dia-
mond Rubber Com-
pany furnishes a
special clip to be used
with their quick-de-
tachable and regular
clincher tires, while
the clip shown in
Fig. 18 (a) is to be
used with straight-side
tires. Attention is
called to the fact that
the proper size bndge

dip must always be used, becatise one made for instance for a
6-inch tire will not fit a 2i-inch tire, and vice versa.

34. Designation of Tire Sizes. — The size of an American
pneumatic tire is designated by first giving, in inches, its out-
side diameter over the tread and then the diameter of the circle
that closely conforms to the outside cross-section of the tire.
Thus, when speaking of a 32" X 4" tire, it means that the

Digitized by

Google

22 AUTOMOBILE TIRES § 11

tire has an outside diameter of 32 inches and that a circle
4 inches in diameter will approximate the external outline of the
cross-section.

Tires are made in certain standard sizes that are agreed on
by tire makers; these sizes are changed, however, from time
to time, as occasion demands. Tires are also made to suit
the wheel rims of foreign cars, in which case their size is stated
in millimeters. The inillimeter is rrhz meter, the length of the
meter being 39.37 inches, nearly.

35. Oversize Tires. — Double-tube tires larger than the
standard sizes are sometimes used in order to increase the cross-
section of a tire air cushion, as well as to give a heavier and more
wear-resisting tread. These are known as overstze tires and are
applied without changing rims. They are i inch larger in
cross-section and 1 inch larger in diameter than the tmiform
sizes with which they interchange. For instance, the oversize
tire for a 32"X4" rim is 33"X4i^

As a general thing, it is advisable to use the corresponding
size of inner tube with any casing, although the Goodyear Tire
and Rubber Company has on the market an inner tube con-
structed especially to be used with a larger sized casing, at least
in the smaller sizes; this practice is uncommon, however.
With this special tube, an oversize casing can be fitted to a rim
and the standard-sized inner tube retained. Thus, an inner
tube intended for a 32"X3i" casing can be used in a 33"X4"
casing. However, unless special provision is made it is not
advisable to make a practice of using an inner tube smaller
than is intended for a casing. An inner tube larger than the
proper size for a casing can also be used temporarily, as in an
emergency. A tube that is too large, however, wrinkles in the
casing and is liable to chafe through quickly or crack at the
short bends of the wrinkles.

Standard sizes of tires can always be recognized by the fact
that the tread diameter is given in even inches; oversize tires
have the tread diameter in odd inches. Thus, a 36" X 4" tire
is a standard size, while a 37" X 4^" tire is an oversize tire.
The use of oversize tires is advisable when standard size tires

Digitized by

Google

§ 11 AUTOMOBILE TIRES 23

on a car are overloaded and hence wear out faster than they
should.

36. Permanent Tire Treads. — The tread of tires is
made in various contours, the most common one being the plain

tread, shown in Figs. 2
to 5. Raised treads of
various forms are also
used extensively for the
purpose of giving pro-
tection against side slip-
ping; some of the most
common examples are
shown in Fig. 21. In
view (a) is shown the
Bailey tread, in which
conical rubber studs
project from the tire.
The Goodrich safety
tread is shown in view
(b). The raised cross-

(h) (e)

Pig. 21

oars tend to prevent fore-and-aft spinning of the driving wheels,
while the longitudinal bars tend to prevent side slipping. The
Fiustone non-sktd tread, view (c), consists of raised rubber let-
ters that grip the road and prevent slipping. Permanently
attached tire treads are sometimes made of leather and studded

Digitized by

Google

AUTOMOBILE TIRES

§11

with steel rivets or studs placed in a manner similar to that
shown in Fig. 21 (a). Many forms of tire treads other than
those mentioned are on the market, each designed with a view
to prevent slipping and each having its pecuUar advantages.

TIRE MAINTENANCE

INFLATION OP TIBES

37. Loads and Air Pressure for Tires. — ^There seems
to be no very dose agreement either among the manufacturers

or the users of tires
as to just what maxi-
mimi load a tire can
carry or what should
be the pressure of in-
flation. This condi-
tion is probably due
to the fact that tires
of the same size are
made of different
thicknesses by tire
makers, and also that
the most suitable in-
flation pressure depends to some extent on the natiu'e of the
road over which the car is run. It is always safe to assume,
however, that a tire will not show appreciable bulging between
the wheel rim and the roadway if it is properly inflated. In
any case, it is not possible to formulate a general statement
as to just how slight, according to actual measurement, this
bulging should be. A thin, flexible tire will naturally bulge
more than a heavy, stiff one, provided both are inflated to the
same pressure.

The lower part of a wheel with a properly inflated tire is
shown in Fig. 22 (a), and a soft tire, as one not inflated hard
enough is called, is shown in (6).

Fig. 22

Digitized by

Google

§ 11 AUTOMOBILE TIRES 25

38. One of the most important things in the care of auto-
mobile tires is to keep them properly inflated. The only prac-
tical way to determine whether a tire is sufficiently inflated is
to use a pressure gauge. Furthermore, if the bad results of
under inflation are to be avoided, it is not enough to test the
pressure at long arid varying intervals but a regular and frequent
test should be made, say, twice a week.

Fixed rules are used by some manufacturers for determining
the proper air pressure for different sized tires. For instance,
the Diamond Rubber Company uses the rule that the required
air pressure per square inch equals the diameter of the cross-
section of the tire multiplied by 18. Thus, a 36" X 4" tire
requires an inflation pressure of 4X18 = 72 pounds per square
inch, by this rule. Other manufacturers use different constants
varying from 15 to 21, while in still other cases no definite rule
is followed, tables being compiled from experience.

39. Table I gives the inflation pressures recommended by
the Firestone Tire and Rubber Company, as well as the safe
load for front and rear wheels on a car without passengers.

40. If an automobile is run at high speed for any length
of time, the tires will be heated considerably and the air pres-
sure within them will thus be slightly increased. Although this
increase of pressure does not endanger a new tire of good
quality, it will do harm to an old tire that has become weak-
ened by long use. It is therefore advisable to reduce the air
pressure in such tires by slightly opening the tire air valve.

41. Methods of Inflating Tires. — ^The means used for
inflating pneumatic tires may be classified imder four general
heads; namely, hand^perated tire air pumps; engine-driven
tire air pumps; spark-plug tire air pumps; and storage tanks
containing compressed air or carbonic-acid gas.

Digitized by

Google

TABLE I

LOAD AND ADEt PRESSURE FOR PNEUMATIC TIRES

Load per Wheel

SiseofTire

Air Pressure

Pounds

Inches

Poundsper
Square Inch

Rear

Front

28X3

350

450

30X3

375

475

32X3

375

475

34X3

400

500

36X3

425

525

29X3i

450

550

30X3f

475

575

31X3

500

600

32X34

525

625

33X3i

550

650

34X3i

575

675

36X3i

625

30X4

550

31X4

575

725

32X4

600

750

33X4

625

775

34X4

650

800

35X4

675

825

36X4

700

850

37X4

725

875

38X4

750

900

40X4

800

950

42X4

850

1,000

32X4*

800

1,000

33X4I

850

1,050

34X4*

900

1,100

35X4*

950

1.150

36X4i
37X4i

1,000

1,200

1,050

1,250

38X4*
40X4}

1,100

1.300

1,200

1.400

42X4i

1,300

1,500

33X5

950

1,200

34X5

1,000

1,250

35X5

1,050

1.300

36X5

1,100

1.350

37X5

1,150

1.400

38X5

1,200

1.450

39X5

1,250

1,500

41X5

1.350

1,600

43X5

1,450

1,700

36X5J

1.250

1,500

37X5i

1,300

1.550

38X5J

1,350

1,600

40X5*

1,450

1,700

37X6

100

1,350

1,600

39X6

100

1,450

1,700

41X6

100

1.550

1,800

Digitized by

Google

§ 11 AUTOMOBILE TIRES 27

HAND-OPERATED TIBE PUMPS

42« Classes of Hand-Operated Pmnps. — ^While tire
inflation by hand-operated means has largely given way to
inflation by power-driven pumps, yet the hand pimip will
doubtless always be used more or less, especially for inflating
the smaller-sized tires.

Hand-operated tire
piraips are made single i I

acting, compressing
the air on the down-
ward stroke only, or
double acting, com-
pressing the air on
both the upward and
the downward stroke.
Double-acting pimips
usually compress the
air in two stages; that
is, the air is partly
compressed on the one
stroke and fully com-
pressed on the next
stroke. Such ptunps
are called dottble-acting
compound tire pumps.

43. Single Act-
ing Hand-Operated
Piunps. — A single-
acting tire air pimip of ^'°' ^
simple construction is shown in Fig. 23, which is a sectional
view of the Pitner single-acting pump. This pump consists
essentially of a barrel a and a piston b that is actuated by hand
by the wooden handle c and the piston rod d. The wooden
handle is first driven into a brass collar e, after which the rod
is screwed through both. The piston b is made air-tight by
means of a leather piston ring / that fits in a groove around the

Digitized by

Google

28 AUTOMOBILE TIRES § 11

piston. An air space behind the leather ring provides an air
cushion that presses the ring against the barrel of the pump.

Air is taken into the barrel of the pump on the upward stroke
of the piston. During this stroke ports g in the piston are open
and air flows through holes in the cap around the piston rod
and into the lower part of the barrel through the ports g. On
the downward stroke of the piston, the ports g are closed by ball
checks and the air contained in the lower half of the pump is
forced out through small holes A, past the ball check-valve t,
and into the tire hose connection /. The check-valve i prevents
air from entering the pimip from the tire on the upward stroke
of the piston.

44. The pump shown in Fig. 23 is so designed that as soon
as the piston passes the small holes h at the base of the pump no
more air can escape and thus a small air ctishion is formed,
which prevents the piston from striking the bottom with a
sudden jar. A felt pad k is placed below the air cushion to
absorb surplus oil and keep it out of tires. An extension, which
is not shown, is placed on the base to receive the foot of the
operator in OTder to hold the pimip while it is being operated.

45. Single-acting tire pumps are also made in forms differ-
ing somewhat from that shown in Fig. 23, but the principle of
operation is, of course, the same. Most pimips make use of
cup-shaped leather washers instead of leather piston rings for
making them air-tight. Such pumps depend on the collapsing
of the cup leather for admitting air to the barrel, and hence are
not provided with ports and check-valves in the piston.

46. Double- Acting Hand-Operated Pump. — ^A t3rpical
double-acting tire pump is shown in Fig. 24, which is a sectional
view of a pump manufactured by the Judd & Leland Manu-
facturing Company. In order to make this pump double acting,
it has two barrels a and 6, each of which is provided with a
piston and piston rod. The barrels are connected at the
bottom by an air passage c, but they are not connected at the
top. The inlet is near the top of the larger barrel a through
two holes, one of which is shown at d, and the outlet is from two
holes located near the top of the smaller barrel 6. The outlets

Digitized by

Google

§ 11 AUTOMOBILE TIRES 29

connect with the tire hose by means of a passage represented
by the dotted lines e in the bracket /. A stuffingbox g that sur-
rounds the piston rod in the upper end of the smaller barrel
prevents air from escaping at that point. Each piston is
provided with a cup-shaped leather
washer; the leather in the larger
barrel is placed so that the piston
operates on its downward stroke,
while the leather in the smaller
piston forms an air-tight plimger
on its upward stroke. Both pistons
are operated by one handle h,

47. Being a double-acting
pimip, air is discharged from the
outlet during both the downward
and upward strokes of the pistons.
During the downward stroke, air
is drawn in at the upper end of the
larger barrel a and fills the space
above the piston. At the same time
the air that was already in the
larger barrel beneath the piston and
in the smaller barrel fe, is forced
past the smaller piston and into the
air hose and tire by way of the out-
let passage e. The air that remains
in the smaller barrel at the end of
this stroke is compressed to a cer-
tain extent.

During the second, or upward,
stroke the air remaining in the
smaller barrel 6 is forced out and „ ^,

mto the tire by the smaller piston.

This air has been previously compressed; hence, on this stroke
the pump is a true compotmd pump. . On the downward stroke,
however, the air that is forced out has not been precompressed.
Besides forcing the air out during its upward stroke, the smaller

Digitized by

Google

30 AUTOMOBILE TIRES § 11

piston also draws air into the pump through the holes d and
past the larger piston, so that both barrels are filled with air at
the end of this stroke and are ready for the descent of the
pistons on their downward stroke, which has been explained.

The successftil operation of this type of tire pump depends on
the condition of the cup leathers, which must be soft and pliable.
When operating properly, air cannot be forced upwards past the
larger piston or downwards past the smaller one, but when
air is forced in the opposite directions the cup leather collapses
and allows it to pass. This action of the cup leathers makes
separate check-valves ttnnecessary.

48. Hand pumps are made with as many as three or four
barrels, three barrels being quite common. Such pumps are
always double acting and usually compoimd as well. A tire
can doubtless be filled more quickly with a double-acting com-
pound pump, but many drivers prefer the more simple single-
acting pump because all of the work is done on the downward
stroke. The greater ease with which this pump can be used
makes up for the longer time required to inflate a tire.

ENOINE-DRIVEN TIRE PUMPS

49. Application. — Many makes of automobiles are now
equipped with power-driven tire pumps that are driven from
some part of the engine. Where such a pimip is not a part of
the regular equipment, provision is made in some cases for its
installation. The engine-driven tire pimip is simply a small
single-acting air compressor, having from one to four cylinders,
that is connected to some moving part such as the magneto or
water-pump shaft, or the transmission shaft, by means of a
metal clutch or by sliding gears. By the use of such a ptimp, an
average sized tire can be inflated in from 1 to 5 minutes and
without the arduous labor necessitated by the hand pimip.

50. Single-Cylinder Engine-Driven Pumps. — ^An

example of a single-cylinder engine-driven tire pimip is given
in Fig. 25, (a) being an external side view and (b), a vertical
section. This pump is used on many Pierce-Arrow automo-

Digitized by

Google

§11

AUTOMOBILE TIRES

biles. It belongs to the cU
valve, the air being admittec
pump is driven from the tra
of a jaw clutch, one member
tire-pump shaft a.

The piston and connecting
structed similarly to those o

H|^»(

completion of the downward stroke of the piston, the inlet
ports b are uncovered and fresh air is drawn into the cylinder.
On the upward stroke of the piston, the check-valve c is lifted
off its seat and the air is f OTced out through the tire hose connec-
tion d. The cylinder of the pimip is air-cooled, being surroimded

Digitized by

Google

32 AUTOMOBILE TIRES § 11

by flanges e for the purpose of increasing the radiating surface.
The moving parts are lubricated by the splash system.

This pimip will work most efficiently when run at 300 revolu-
tions per minute. It is started and stopped by a lever, by means
of which the jaw clutch can be engaged or disengaged. The
pump should be put into action with the engine running slowly
and should not be run at a greater speed than just given; other-
wise, it will waste power by
heating.

51« Diapliragm Tire
Pump. — ^A single-cylinder
tire pump of peculiar con-
struction is shown in Fig. 26,
which is a part sectioiial view
of the Taylor "Noil" dia-
phragm pump. This pump
is so constructed that it is
impossible for lubricating oil
to become mixed with the air
that is being forced into the
tire, hence, the name Noil.
The ordinary reciprocating
piston is not used in this
pump but, instead, the upper
end of the connecting-rod a
pj^ 26 terminates in a large, mush-

room-shaped disk, to which is
secured the soft rubber diaphragm b. This diaphragm is also
secured to the body of the pump by being clamped between
it and the head, or cap c, thus completely separating the lower
portion of the pump from the upper portion, where the air is
compressed.

The connecting-rod is reciprocated by means of an eccentric
on the shaft d. On the downward movement of the connecting-
rod and diaphragm, the inlet valve e, which is supported by a
bronze spring /, is drawn open and air drawn into the pump.
On the upward stroke, the diaphragm forces the air out past

Digitized by

Google

§ 11 AUTOMOBILE TIRES 33

the ball check-valve g and by way of the tire hose connection h,
to the tire.

The Taylor Noil pump can be driven from any exposed moving
shaft but is usually driven from either the magneto or the water-
pump shaft. The sliding gear t is operated by a lever /, by which
it can be thrown in and out of mesh with a gear on the revolving
shaft. This pimip operates most efficiently at a speed of about
600 revolutions per minute. Flanges on the cover of the pimip
help to radiate the heat resulting from the compression of the air.

52, Multiple-Cylinder Tire Pumps. — ^The most com-
mon form of mtiltiple-cylinder tire pimip is air cooled and has

Fig. 27

the cylinders cast in one piece. Usually the pimip has either
two or four cylinders arranged vertically, although an exception
to this rule is the Abbell pimip, which has three cylinders
arranged horizontally. The pistons are driven either by
cranks or by eccentrics, the lower ends of the connecting-rods
fonning the straps. In some pumps the pistons are plain and
carry no rings, while in other cases they are provided with rings
like gasoline-engine pistons. Pimip cylinders are sometimes
surrounded by a water-jacket and cooled by water, although
this is usually deemed an ttnnecessary refinement.

222B— 47

Digitized by

Google

34 AUTOMOBILE TIRES § 11

63. Fig. 27 shows a part sectional view of the Stewart four-
cylinder air pump. The four cylinders are cast in one piece and
are air cooled, being provided with horizontal flanges a for
increasing the heat radiating surface. The four pistons, two
of which are shown at b and c, are driven by eccentrics from the
shaft d. The pistons are perfectly smooth, being simply small
cylindrical pieces that have been . grotmd accurately to size.
The crank-case is divided horizontally in line with the shaft d,
the upper half being cast integral with the cylinders. The
air inlets e are screened. The outlets / are provided with
ball check-valves and all open into a common passage g, from
which the air-hose connection h on top of the forward cylinder
leads. The mechanism t, located at one end of the pimip, is
for the purpose of connecting it to or disconnecting it from the
driving shaft.

54. In operation, the action of the pimip is the same as that
of the Pierce-Arrow single-cylinder pump. On the downward
stroke of the piston, the inlet ports e are imcovered and air
rushes into the cylinder. On the upward stroke, the piston
compresses the .air and forces it out past the ball check-valve
into the outlet passage g, thence to the tire connection and
the tire.

8PABK-PLUO TIBE PUMPS

66. Tire pumps operated by the alternate compression and
suction in the engine cylinder are made up in slightly different
forms but operate on the same general principle. They are
made to screw into the spark-plug hole of a cylinder, so that,
when it is desired to inflate a tire, a spark plug is removed from
one of the cylinders, the ptunp is screwed in its hole, and the
motor is run idly on the remaining cylinders.

56. An example of the spark-plug tire pump is the Dewey
pump, shown in section in Fig. 28. A differential, or double,
piston is utilized, consisting of a large piston a that works in
the outer cylinder 6, and a smaller piston c that works in an inner
cylinder d, the two pistons being connected by means of a hol-
low rod e. The pressure in the engine cylinder to which the

Digitized by

Google

§ 11 AUTOMOBILE TIRES 35

pump is attached forces the larger piston a upwards diuing the

compression stroke in that cylinder. The pressure that is

developed during this stroke varies from 50 to 75 poimds per

square inch, depending on the compression

pressure of the engine. This pressure per

square incji is increased by the use of the

double piston; hence, the smaller piston c

is capable of pumping air into the tire at

a much higher pressure per square inch

than is developed at the larger piston o.

67. The operation of the spark-plug
tire pump is comparatively simple. On the
downward stroke of the engine piston
(either the suction or the working stroke),
a partial vacuum is formed in the pump
cylinder b beneath the larger plunger o and
the pimip pistons are forced downwards by
atmospheric pressure through the open-
ings / in the top of the pimip cylinder. At,
or about, the time that the ptunp plunger o
reaches the bottom of its stroke, the
breather valve g opens and allows fresh air
to be drawn into the engine cylinder. This
fresh air from the engine cylinder flows
through the hollow rod e into the space
in the inner cylinder d above the small
plunger c, at the beginning of the com-
pression stroke of the engine piston. The
plungers are forced upwards during this
stroke and the air in the inner cylinder is
pumped into the tire by way of the tire
hose connection h. A ball check-valve i
prevents air from flowing back into the
pimip from the tire, and a similar check- ^'°* ^®

valve / prevents air from flowing from the inner cylinder back
into the outer one. The pistons of the ptunp are fitted with
cup-shaped leather pltmgers, as shown. Different sized nipples k

Digitized by

Google

36 AUTOMOBILE TIRES § II

can be secured from the makers of this ptimp to coM-espond to
the different sizes of spark plugs.

It is claimed by the makers of the Dewey pump that no
gasoline vapor from the engine cylinder reaches the ptunp on
accoimt of the amount of pure air taken in through the breather
valve.

INFLATION FROM STORAGE TANKS

58. Storage tanks containing compressed air are usually
foimd in all the better garages in the large cities. The air is
pimiped into the storage tank by an air compressor, which may
be belt driven, or driven by a gasoline engine, or by an electric
motor.

There are on the market small storage tanks for tire infla-
tion that may be carried in the automobile. Such tanks, when
empty, may be exchanged for full ones at various supply
depots throughout the country. If cost is no consideration,
the use of portable storage tanks is ideal for ease of inflation.
However, as the air or carbonic-add gas is stored in the tank
under great pressure, extreme care must be exercised not to
inflate the tires too much. It is advisable always to use a tire
pressure gauge when inflating from a storage tank. Each
portable tank will usually inflate from two to twenty-five tires
with one filling, depending on the size of the tires.

The Prest-o-Tire tanks, which are of this type, are each
charged with 5 potmds of liquid carbonic gas at a pressure of
900 pounds per square inch. If this gas is allowed to escape
too rapidly the rapid decrease in pressure causes it to freeze,
forming a snowy substance.

PUMP CONNECTIONS AND PRESSURE GAUGES

69. Tire Pumps Pitted With Gauges. — ^There are
on the market tire air pumps that have a pressure gauge incor-
porated to indicate the pressure within the tire. When such
a ptimp is used, the hose connection to the tire au* valve must
be constructed so that the tire air check- valve can be pushed
and held off its seat. If this kind of a connection is not used,

Digitized by

Google

§11

AUTOMOBILE TIRES

(a)

the presstire gauge will register the presstire to which the
pump compresses air, instead of the pressure existing in the tire.

60. Pump Connections to Tire Air Valves. — In

Fig. 29 are shown two common types of air-ptimp connections.
The one shown in (o), known as the Perfection coupling, has
the outer casing a threaded internally to fit the outside thread
at the end of Schrader valve stems. A fiber washer b makes a
tight joint against the end of the valve stem and also against the
end of the air barrel c, to which the hose leading to the sotirce
of air supply is attached.
Owing to the construc-
tion, the outer casing o
and its locknut d can
turn freely on the air
barrel, so that the hose
will remain stationary
while attaching or de-
taching the connection
to the tire valve stem.

The form of connec-
tion shown in (6),
known as the Keno
Number 3 coupling, car-
ries the hose, attached
to the nipple o, at right
angles to the tire valve
stem. The connector b is threaded at c to fit the inside thread
at the end of Schrader valve stems. A small screw d passes
through the center of the connector 6. When this is screwed in,
it opens the air check-valve of the tire valve stem, thus adapt-
ing this connection to tire pumps fitted with a pressure gauge.

Most ptimp connections can be obtained with or without a
central teat or screw for holding the air check-valve open. The
nipples of pump couplings are made to fit tire-pump hose having
an internal diameter of ^ inch; larger ptimp hose is on the
market, but is used only in connection with large compressed-
air storage tanks.

Pig. 29

Digitized by

Google

38 AUTOMOBILE TIRES § 11

61, While the Schrader valve stem is today the standard
device used on American inner tubes, there are in use many

foreign inner tubes having tire air valves that differ from the
Schrader valve stem. The foreign valve stems mostly used
are the Michelin and the English Dunlop.

To permit the same air hose to
be attached to any one of the three
tire valve stems mentioned, the
form of connection shown in Fig. 30
has been placed on the market. In
this type of connection, the casing a
. ' is threaded internally to fit the out-

side thread of the Michelin tire valve stem; the adapter b is
threaded externally to fit the casing a, and internally to fit the
outside thread of the English Dimlop tire valve stem; and
the adapter c is threaded
at one end to fit the in-
ternal thread of the
adapter 6, and at the
other end to fit the in-
ternal thread at the end
of the Schrader tire-valve
stem.

62. A connection
known as the universal
pump connection, which
may be fitted to any
valve, is shown in Fig. 31.

It is attached to the tire valve by simply pressing it on, when
a rubber washer holds it firmly to the valve stem. It is
removed by pulling it off. The rubber washer can be replaced
by a new one when it is worn out.

Digitized by

Google

§ 11 AUTOMOBILE TIRES 39

63. Tire Pressure Gauges. — As insufficient inflation
is the most prolific source of tire troubles, and as not even an
expert tire man can tell by observation or by feeling a tire
whether or not it is properly inflated, a tire pressure gauge

{

should be used not only when inflating tires, but also for peri-
odically testing the inflation presstire.

64, There are several reliable tire presstire gauges on the
market. One type of gauge is shown separately in Fig. 32, and
in Fig. 33 this same gauge is shown attached to a tire valve
and pump. Referring to Fig. 32, the knurled nut o, threaded
inside to fit the outside thread of Schrader valve stems, is
used for connecting the gauge to the tire-valve stem. The

Digitized by

Google

40 AUTOMOBILE TIRES § 11

hose from the inflating pump is attached to the lower middle
part of the gauge after the cap c, which is the same as that used
on the valve stem of the tire, is removed. By screwing in the
knurled head b after the gauge has been attached to the tire
valve, the small air valve in the valve stem of the tire is forced
from its seat. The air valve, which then operates as a check-
valve, is in the part of the gauge immediately above the cap c.
An indicating hand moves over the dial e in the cylindrical part
of the gauge shown at the left-hand side. The dial
is graduated to indicate the air pressure in poimds
per square inch.

65. Tire pressure gauges that are less expensive
than that shown in Fig. 32 are on the market.
Some of these operate on the same principle but are
not provided with a device for forcing the small air
valve in the valve stem from its seat. A pump
connection like that shown in Fig. 29 (6) shoxdd be
used in such a case.

66. Another simple form of tire pressure gauge
is the Schroder Universal tire pressure gauge, shown
in Fig. 34. A tire is tested by this gauge by simply
holding the bottom a, in which there is an opening,

to the tire valve. The air enters the air chamber in the gauge
and forces the indicating sleeve b out; the pressure in the tire
is read on the sleeve. The indicating sleeve remains at the
point to which it has been forced by the air pressure tmtil
pushed back in place.

TIRE PROTECTORS AND ANTISKID DEVICES

67. Detachable Tire Protectors . — ^E ver since the advent
of the pneumatic tire, inventors have been devising means of
protecting it from puncture and at the same time render-
ing it less liable to side slip. In some cases, the devices have
asstimed the form of permanent tire treads; in other cases,
they have taken the form of detachable protectors that are
made in various styles and attached to the tire in a variety
of ways.

Digitized by

Google

§ 11 AUTOMOBILE TIRES 41

A typical detachable tire protector, known as the Woodworth
tread, is shown in Fig. 35. This protector is a steel-studded
leather cover that is shaped to fit the tread of a tire and is held
on by means of coil springs along each side. Some of the earlier
Woodworth treads were held on by means of an endless crimped
wire ring. The tread consists of an outer layer of leather, a
middle layer of canvas, and an inner layer of thin leather.
The studs on the middle portion have heads about i^ inch
thick; in addition to these studs there are two rows of thin
head rivets on each side. The
protector is applied while the tire
is deflated and is intended to be
held in place by friction when the
tire is pumped up.

Although tire protectors im-
doubtedly reduce the liability of
puncture and skidding, they slightly
reduce the resilience of the tire and
the speed of the automobile.

68. Iimerliners. — Inside tire
protectors, made up of fabric and
rubber and inserted between the
tire casing and the inner tube, are
sometimes used to reinforce tire
casings. These find their best ap-
plication in worn or injtired casings,
but they may also be used in new
tires, although it is claimed by

some that in new tires their ad- ^'°* ^

vantage is offset by the extra heat and wear that they cause
and by their added weight. Several forms of innerliners are on
the market.

69. The Interlock inner tire, shown at a in Fig. 36, is an
endless inside casing molded to fit the various sizes of tires. It
fits between the regular tire casing b and the inner tube c,
lapping over, or interlocking, on the inside, or next to the rim as
shown at d.

Digitized by

Google

42 AUTOMOBILE TIRES § 11

Another form of innerliner is shown in Fig. 37 (o), which
is a view of the K and W Patent Reliner. Instead of being
endless like the Interlock, this reliner is split transversely.
Innerliners of this form are held in place between the tire casing

and the inner tube by a
coating of cement, which
may be put on at the
factory or when the re-
liner is applied. They
come from the factory
rolled up as shown in
view (6).

A third form of inner-
liner is the endless type
that does not overlap
along the edge. An ex-
^'°*^ ample of this form is

shown in cross-section o in Fig. 38; this particular reliner is sold
imder the trade name of Innershu. It is similar to the Inter-
lock in that it is endless like a tire casing but it has no
overlapping flaps; the edges simply taper off at the edge of
the casing.

70. Tire Clialns. — In Fig. 39 is shown the Weed antiskid
tire chain, which is the form of chain that is used exclusively to

Pig. 87

prevent tires from skidding. However, such a device will not
protect them from pimcture. The complete chain consists of
two circumferential chains, one of which is shown at a, which

Digitized by

Google

§ 11 AUTOMOBILE TIRES 43

pass around the wheel jtist outside the rim, and are con-
nected together by numerous cross-chains that pass over the
tread of the tire. The ends of the circttmferential chains are
fastened together by means
of very simple fasteners, as
shown at 6, one of which is
provided in each chain.
Both fasteners lie between
the same pair of cro^-
chains. To put the chain
in place, the wheel is jacked
up or the chain is stretched
out on the ground, or floor, ^*° ^

either in front of or behind the wheel, and the wheel run on it.
The chain can then be brought over the wheel and fastened in
place. To remove the chain, the fasteners are opened and the

chain permitted to drop to the
ground, after which the wheel is
run from it.

71. Mud-Hooks.— If an

automobile is running on very
wet and muddy roads that are
not macadamized, the tire chains
sometimes do not give sufficient
grip to drive the car, in which
event the driving wheels spin
around and the chains dig into
the roadway luitil the axle or
some other part of the car rests
on it.
For running on extremely soft
pj^ g^ mud roads, a mud-hook of the

form shown in Fig. 40 will be
found very useful. When properly placed, this type of mud-
hook projects far enough from the tire to get a good grip on
the mud. It is advisable to put at least fotir hooks on each
driving wheel, placing them at equal distances aroimd the

Digitized by

Google

44 AUTOMOBILE TIRES § 11

wheel. If only one mud-hook is tised on each wheel, as is
sometimes recommended, it will grip the road imtil the rota-
tion of the wheel lifts it from the roadway. If the engine is

then pulling hard and the

clutch is in full engagement,

as is the ordinary condition

of operation imder the drcum-

stances, the driving wheels

will spin around imtil the

hooks, one on each driving

wheel, come into contact with

the roadway again. This will

suddenly stop the rotation of

the wheels and cause excessive

stresses on the transmission system, especially if the clutch is

one that holds very tight when in full engagement. The use of

four mud-hooks on each wheel will prevent spinning to a great

extent and thus prevent any great stresses on the engine.

Digitized by

Google

AUTOMOBILE TIRES

(PART 2)

TIRE DETERIORATION AND REPAIRS

TTRE DETERIORATION

CAUSES OF TIRE FAILURE

!• XJnder-Inflatlon. — If an automobile tire is not stifl&ci-
ently inflated to keep it nearly round when carrying the weight
of the car and the passengers, it is subject to rapid wear both
alongside the bead at the rim of the wheel, called rim cuttings

and throughout the body of the tire. The excessive bending
of a tire that is not fully inflated has a tendency to cause exces-
sive heating, to separate the layers of fabric, and to work the
rubber tread loose from the carcass.

COPYRiaHTBD BY INTKRNATIONAL TKXTBOOK COMPANY. ALL RIOHTS RBSBRVKD

811

Digitized by

Google

46 AUTOMOBILE TIRES § 11'

If a tire is extremely soft on account of complete or nearly
complete deflation, it flattens at the bottom where it rests on
the roadway, taking a form similar to that shown in Fig. 1.
All the load is then practically carried by the clinch of the rim
or by the retaining rings or flsmges, as the case may be. The
result is that the casing is injured by rim cutting where the
clinch or retaining rings bear on it, and the inner tube may be
cut through in places where it is pressed together just over the
clinch or retaining rings. In addition to this, the heads of the
tire lugs in a plain clincher type, as well as the valve stem end
inside the rubber tube, are liable to be injured, especially if the
roadway is very imeven or rocky.

A tire that has become de-
flated on account of leakage
at the valve, a ptmcture, or a
blow-out should never be run.
If no spare tire is available,
the rim may be wrapped with
rope or the car may even be
run on the bare wheel rim.
While this may spoil the rim,
wheel rims are very cheap in
comparison to tires.

2. It frequently happens
that a tire becomes soft on account of leakage through the air
valve and also past the cap that screws on the valve stem. A
test for such leakage can be made by immersing the end of the
valve stem in water contained in a glass or some other vessel,
as illustrated in Fig. 2. The leak is manifested by air bubbles
issuing from the end of the valve stem. A little saliva placed on
the end of the valve stem will indicate a leak in the air valve
after the cap is removed from the stem. If leakage occurs when
the cap is in place, it is of course an indication that both the
valve and the cap leak. The repair of either one of these
parts will generally stop the leak.

A leak through the cap of the valve stem is almost invariably
due to deterioration of the small rubber disk packing in the cap.

Digitized by

Google

§ 11 AUTOMOBILE TIRES 47

the disks being cut through or wrinkled on accoimt of screwing
the cap into place. The simplest remedy for such a leak is to
tise a new packing disk in the cap.

About the only satisfactory remedy for a leaky tire air
check-valve is to replace it with a complete new one. Air
check-valves are so inexpensive that it is about as cheap to
put in a new one as it is to ptirchase and carry any of the
extra rubber parts. About the only rubber part that can be
removed from the air valve and replaced by a new one is the
cone-shaped piece of rubber that fits against the end of the valve
stem to make an air-tight joint. It is practically impossible to
renew the rubber valve seat satisfactorily.

3. The tool shown in Fig. 3 is intended for smoothing
and dressing up battered valve stems of inner tubes. The
tap a is used for clean-
ing up the thread inside

the tubular valve stem;

the die b for recutting ||

the outside thread on the ^

valve stem; and the

facing cutter c for

smoothing oflE the end

of the valve stem where

the rubber packing disk presses against it. The tubular part

above c slips freely over the end of the valve stem to hold

the tool in place when smoothing the end of the stem. The

slotted end d is used to remove the small air valve from the

hollow valve stem and to screw the valve into it.

4. One effect of driving a car with a soft tire is clearly
shown in Fig. 4, which illustration has been made from an
actual tire, and shows a part of the tire on which the tread has
torn loose from the carcass. The only way that such an injury
can be repaired is by retreading the tire; since, however, the
tearing loose of the tread due to running the tire soft is usually
accompanied by serious injury to the tire fabric, it is an open
question whether or not it will pay to retread the tire. The
advice of an expert tire repairman should be sought and taken.

Digitized by

Google

Fig. 6 Fig. 7 48

Digitized by VjOOQ IC

§ 11 AUTOMOBILE TIRES 49

An example of rim cutting is shown in Fig. 5. Here the side
walls of the tire are broken next to the beads. If the damaged
part is small, a repair can be made.

5. Improper Driving. — ^Either skidding the wheels on a
dry road by a too powerful application of the brakes or causing
the wheels to spin by starting the car too suddenly, is extremely
injurious to the tires, because the abrasion of the tires against
the road cuts and tears away the tread of the shoe. If the
brakes are applied so hard as to prevent the wheel from turning
when the car is traveling at considerable speed, the heat due
to the sliding of the tire on the road will melt the rubber, and the
destruction of the tire will then be exceedingly rapid. The
restdt of thus locking the rear wheels and causing them to slide
is shown in Fig. 6, whefe the casing is shown worn through the
tread and part of the carcass.

Continued driving in street-car tracks or wheel ruts will wear
off the sides of the tire throughout its entire circumference. A
section of a tire that is rut worn is shown in Fig. 7 ; the exposed
tire fabric can be clearly seen.

Ttiming a comer at high speed causes an excessive side
presstire on the tires. This, of course, has a tendency to tear
the bead loose from the other portion of the tire. The side
pressure may be sufficient to pull the tire from the rim, to
bend the axle, or to break the wheel. Sharp comers should
be turned at slow speed.

6. Pulling Loose of Tire Fabric. — ^A tire shoe some-
times fails because the fabric pulls loose along the outside
of the shoe just above the angle between the bead and the
main body of the tire. When the fabric thus pulls loose
a large blow-out of the inner tube generally follows. Unless
closely looked for, defects of this kind are sometimes difficult
to locate, because as soon as the tire is deflated the torn part
of the fabric will spring back against the body of the tire.
The faxdt can be readily detected by bending the bead of the
tire down by hand while the tire is off the wheel.

7. Chafing of Inner Tube. — Chafing of the inner
tube is a frequent source of tire trouble. The chafing xdti-

222B— 48

Digitized by

Google

50 AUTOMOBILE TIRES § 11

mately rubs a hole completely through the tube, so that it
becomes deflated. The best, and probably the only way to
prevent a tube from chafing is to use a liberal quantity of some
such substance as talcum powder, French chalk, graphite, or
powdered soapstone. The inner tube should fit the shoe
properly; under no condition should it be too large.

8. Blisters. — ^Blisters, which frequently form on the
tire shoe, are due to various causes. If a tire is faulty, the
kneading action created by rolling over the road sometimes
works the outer coating of rubber, that is, the tread, loose from
the outer layer of fabric. Another cause of a blister is a cut
through the tread. Sand and mud work in through this cut
and gradually tear the rubber from the fabric. A blister
formed in this manner is always solid because it is filled with
mud and sand. Blisters on a tire shoe cannot be remedied very
well outside of a tire-repair shop.

9. Non-Parallellsin of Wheels. — Improper alinement of
the wheels, especially of the front wheels, is a common source
of undue tire wear, because then the tires, instead of rolling over
the road, will roll and sUde at the same time. The effect is to
grind oflE the tread and ruin the tire. The appearance of a
front-wheel tire injured from this cause is shown in Fig. 8. If
it is thought that front wheels are out of alinement, they can be
tested by measuring the distance between the two wheels with
a stick, both ahead of and behind the axle. The remedy is to
correct the disalinement and have the tires retreaded if they are
still in a condition to warrant the expense.

Improper rear-wheel alinement is confined to cars of the
chain-driven type, and can always be traced to a bent axle.

10. Improperly Pitted Tire Chains. — In order to pre-
vent undue wear from tire chains, they should be adjusted to
the tires loosely so that they strike the groimd ahead of the tire.
If adjusted too tightly they bind and tear the tire as shown in
Fig. 9. Worn chains that are reversed will give a similar effect,
the sharp edges cutting the tire in a manner similar to tight
chains.

Digitized by

Google

Fig. 8 Fig. 0

51 Fig. 10

Digitized by VjOOQ IC

52 AUTOMOBILE TIRES § 11

Tire chains should not be used except when it is necessary
and then they should be fitted loosely enough to work around
the tires, and thus not press into the tread always at the same
places. Under no consideration should tire chains be tied to
the spokes of the wheel; they must be left free to creep
around the tire.

11. Stone Bruises. — ^A tire running over a heavy stone
or similar obstacle may cause a blow-out immediately or the
injxiry may not become known for a long time, but a blow-out
sooner or later is practically inevitable. The bruise may leave
no mark on the outside of the tread but the fabric inside is
broken as shown in Fig. 10, which shows the casing turned
inside out. The result of a stone bruise is that ultimately the
pressure in the inner tube causes a rupture at the bruised and
hence weakened part of the tire, followed by a rupture of the
inner tube; such a rupture is called a blow-out.

12. Additional Causes of Undue Tire Wear. — ^Aside
from the various causes just given there are several other causes
that may produce a rapid wear of tires. Permitting tires to
stand on an oil-soaked floor will cause the rubber to deteriorate
rapidly, because oil has the eflEect of rotting rubber. Letting a
car stand for months imused on inflated tires will stretch the
fabric of the tires locally; the car should be placed on props
when laid up.

One rear-wheel tire may wear faster than the other on account
of the brake on that wheel taking hold better. This may cause
one tire to slip on the road while the other wheel holds but
little, and hence its tire is but little retarded.

PRESERVATION OF TIRES IN STORAGE

13. If an automobile is to be laid up for some time, say
a week or so, it is an excellent plan to take the weight off the
tires by putting the machine on four blocks or jacks; in fact,
many owners do this every time they come in from a run.
In this way, the fabric of the tires is relieved of local stresses
and the life of the tires is increased. There is no need of

Digitized by

Google

§ 11 AUTOMOBILE TIRES 53

deflating the tires when the machine is laid up for only a short
time.

If an automobile is to be laid up for a long time, say for the
winter, it is advisable to remove, the tires and inner tubes
from the rims. The casings should then be thoroughly cleaned
and carefully examined both inside and outside, and all needed
repairs made at a properly equipped tire-repair establishment,
unless, of course, the operator has the fadUties and is capable
of making the repairs himself. After removing all rust and
dents, the rims should be painted. Various prepared rim paints
are on the market, or an excellent rim paint may be made by
mixing dry flake graphite with shellac. The tires may then
be replaced on the rims after the paint has dried,, and slightly
inflated. The weight should be taken oflf the tires by placing
fotir blocks or jacks tmder the axles; also, the place in which the
machine is stored should be dry and not subject to extremes of
temperature.

If a machine must be stored in a damp or a very hot or very
cold place for a long time, it is advisable to remove all tires to
a dry place that has a fairly even temperature. The tubes
and cases may be wrapped separately and stored in some cool,
dark, dry place.

The greatest enemies of tires and tubes in storage are intense
light, expostire to heat in excess of 75® F., and dampness.
Guarding against these by selecting a proper place for storage
will obviously prolong the life of the tires.

Inner tubes are stored best when slightly inflated, using
just enough air in them to retain their circular form. If
they are folded, cracks are liable to develop in the folds of
old tubes.

ROADSIDE TIRE REPAIRS

TIBB TOOLS

14. Tire Irons. — Several tools are required to remove
and replace a regular clincher tire with rapidity and ease.
For tires up to, say, SJ inches in cross-section, a pair of tools

Digitized by

Google

AUTOMOBILE TIRES

§11

^"""^^^ik^

Fig. 11

of the form shown in Fig. 11 or a pair of tools of the form
shown in Fig. 12 may be used. Both tools are called tire irons.

That shown in Fig. 11 is the

Standard while that shown
in Fig. 12 goes by the trade
name of Eureka. The
latter consists of a handle a
and tapering blade b with roimded comers. This tool is some-
times called a tire prodder.

In the absence of regular tire irons, the two halves of a
broken spring leaf make an excellent substitute. Care should
be taken, however, to round the edges with a fine file or by
grinding, so that there
will be no sharp edge
to cut the tire or tube.

Fig. 12

15. Detacliing Tools. — ^Although the largest tires can
be handled with a pair of tire prodders, or tire irons, the labor
of detaching and attaching clincher tires can be lightened by
the aid of various other tire tools. Thus, if the casing of a
clincher tire is very stiflf or adheres to the wheel rim so tightly
at the bead that the ordinary tire prodder
cannot be inserted between the bead and the
clinch of the rim without great difficulty, a
detaching tool of the form shown in Fig. 13 can
be used to force the shoe loose from the rim.
This tool is known as the Springfield tire tool.
The handle, or hand grip, a has two arms,
one of which extends outwards and toward
the left, as shown at 6, and carries at the end
a wooden roller c that bears against the spoke
d of the wheel when the tool is in use. The
arm b is offset to clear the spoke. The other
arm e of the handle has passing through it a
push piece/ that bears against the casing just
outside the bead. When the handle a is pulled
away from the wheel, the pusher / forces the bead out of the
clinch of the wheel rim.

Fig. 13

Digitized by

Google

§ 11 AUTOMOBILE TIRES 56

In Fig. 14 is shown what is known in the trade as the Coiv-
tifienkU tire tool, together with the method of applying it to
force the bead of a tire away
from the rim to permit inser-
tion of the tire irons.

16. Tire Fork. — Ordin-
arily, one of the hardest parts
of the work in removing a
regular clincher tire or re-
placing it is the lifting of
the shoe to permit the re-
moval or insertion of the tire Pic. i4

lugs and the inner-tube valve stem. This task is ren-
dered comparatively easy, however, if a properly shaped
lever is at hand. There are many tools for this purpose on
the market, a very convenient one being the Michelin tire fork
shown in Fig. 15. The tire fork is applied by inserting the
prongs of the fork between the bead of the tire and the clinch
of the rim, one prong on each side of the valve stem, and thus
lifting the shoe while the stem is being removed from the wheel.

17. Qulck-Detacliable Tire Tools. — ^Various forms of
tools designed to accomplish the easy removal of quick-detach-
able tires from their rims are sold in the market. A common
tool, which goes by the trade name of Bryant tire tool, is shown
in Fig. 16 (a). This tppl is used for forcing back the removable
clinch, or flange, of the rim while the locking ring is being

removed by a screwdriver
or some other tool, as
shown in (fc). It is es-
sential that a tool for this
ptupose be self-locking
so that the clinch will
remain back while the
^'^' ^^ locking ring is being

removed. The one illustrated automatically locks itself when
on the full inthrow as shown. Others are constructed on the

Digitized by

Google

AUTOMOBILE TIRES

§11

principle of the screw, ratchet, or togglejoint, all of which are
self-locking.

A tool of the fonn shown may also be used for forcing the
rusted bead of a tire away from the rim, on either a quick-
detachable clincher tire or a regular clincher tire.

HANDLING OF CLINCHER TIRES

18. Removing the Inner Tube. — One of the most
important, things to bear in mind when removing or replacing a
tire is that the inner tube must be handled with great care.
This tube is made of rubber without any strengthening fabric,
and may therefore be easily pimctured, cut, or torn either
by the tools used or by some of the parts that attach the outer

shoe to the rim of the
wheel. Care must also
be taken that the inner
tube is not left pinched
between any of the
clamps, between the air
valve and the outer shoe
of the tire, or between
the different parts of the
outer shoe. The tools

I used for removing and
replacing should never
have sharp edges or cor-
ners, because they will
be liable to injjire both
the inner tube and the

Pig. 16 shoe.

The ordinary clincher tire used on a soUd wheel rim prob-
ably requires more skill and care for its handling than any other
form of tire. This type of tire is still being used on a large
ntimber of old cars and on some new smaller cars, notably the
Ford Model T, hence, the method of handling it will be given
somewhat in detail, especially as the instructions may also be
largely applied to quick-detachable tires.

Digitized by

Google

§ 11 AUTOMOBILE TIRES 57

19. In order to remove a tire, first jack up the wheel so as
to relieve the tire of its load; then deflate the tire, if deflation
has not already occtirred,
either by pressing in-
wards on the small solid
valve stem that appears
in the middle of the valve,
or preferably by remov-
ing the valve insides.

Next, unscrew the
large nut from the large
tubular stem of the valve, j
and push the stem in^
through the wheel rim.

If the stem sticks in the

wheel rim, it can be forced in by pressing with a piece of wood
against the valve stem. In case tire lugs are used, their nuts
should be loosened and the lugs should be pressed inwards in
the same manner as was done with the valve. After this is
done, insert the thin point of one of the tire prodders between
the tire and one edge of the rim, as illustrated in Fig. 17, pushing
the tire over with the hand or foot. In case no tire prodder is
at hand, the tire can be loosened by placing a roimded block
of wood against the side of the shoe and striking the block with

a hammer.

Next, insert both prod-
ders about 1 foot apart
under the bead of the tire
on the side of the wheel
opposite the valve of the
inner tube. Bring the
handles of the tools to-
ward the hub of the wheel
so as to pry the bead out
of the rim, as shown in
^'°- ^® Fig. 18, moving the tools

nearer together if necessary. In case the tire is very stiff, one
of the tools can be held by one's knee or foot, so as to keep the

Digitized by

Google

58 AUTOMOBILE TIRES § 11

bead out, and the other tool worked along by hand away from
the first tool until enough of the bead is removed to remain out
of its own accord. The remiainder of the bead can then be
worked off with one of the tools or by hand.

After removing one side of the tire from the rim, grasp the
edge of the tire with one hand at the point farthest from the
valve stem of the inner tube, and pull the tire out from the
rim far enough to insert the other hand to pull out the
inner tube. The inner tube should be removed carefully

Fig. 19

on account of its weakness. If it sticks to the casing, it should
not be pulled very hard. The tube sometimes adheres tightly
to the casing on accoimt of having been heated by fast nmning,
or because some cement on a patch has been allowed to get
between them. If the inner tube sticks so tightly that it can-
not be safely pulled out, it can be loosened with a little gasoline.
The tube should be removed as soon as possible after the gasoline
has been put in, so that the latter will not have time to act suffi-
ciently on the rubber to injure it seriously. The gasoline

Digitized by

Google

§ 11 AUTOMOBILE TIRES 69

will generally leave the tube somewhat sticky. After all
the inner tube except the portion just at the valve stem has
been removed, the two tire prodders can be inserted as far
as possible imder the shoe, one tool on each side of the valve
stem and between the casing and inner tube. The outer ends
or handles of the tools can then be brought together as in Fig. 19,
and the tire lifted up with one hand on the tools while the valve
stem is removed from the rim with the other hand.

20. A good plan in case the pimcture can be located before
the inner tube is completely removed from the shoe is to mark
the tube where it is pimcttired and then inspect the shoe in
the neighborhood corresponding to the pimcture in the tube
for the purpose of locating a tack or nail that may have caused
the trouble. This inspection can be made by rubbing the
hand around the inside of the shoe. If this is not done, another
tube that is put into the shoe will be immediately punctured
by the tack or nail still remaining in the shoe. If a nail or a
piece of wire is foimd sticking through the casing for some
distance, the tube should be inspected for two holes, opposite
each other, caused by the nail piercing both sides of the tube.

A small hole can be located by inflating the tube and then
immersing it in water. However, the tube should not be
inflated enough to stretch it much; if inflated too much it
will suddenly expand at one point and is liable to burst if not
caught quickly in the hand. It may be necessary to stretch the
tube by hand in order to open the hole so that air will escape.

Before putting in another tube, the inside of the shoe should
be cleaned so as to remove all loose dirt and sand. Both the
tube and the inside of the shoe should be liberally coated with
talcum powder, French chalk, powdered soapstone, or flake
graphite, before putting them together, and the inner tube
should be deflated as nearly as possible. This can be done by
rolling up the tube, beginning at the part farthest from the air
valve, which must be either pressed down during the operation
or removed in order to let the air escape.

21. Removing a Clinclier Casing From Rim. — If the

casing, or shoe, of a clincher tire is to be completely removed

Digitized by

Google

60 AUTOMOBILE TIRES § 11

from the wheel, the tire damps, provided any are used, mtist
be taken out after removing the inner tube. The clamps can
be removed after prying the tire away from the rim, as when
removing the valve stem of the inner tube. The complete
removal of the shoe is then generally easily accomplished.

22. Care of Rims. — If a tire that has been in place for
some time is removed, it will be foimd that the rim is more
or less rusted. The rim shotdd therefore be cleaned and
smoothed before the tire is put on again. The rust can be
removed by scraping. Especial care must be taken to see that
the clincher part of the rim, into which the shoe bead fits, is
thoroughly clean. Rust collecting under the clinch may pre-
vent the bead from going entirely into the proper position.
After the rust is scraped oflF, the rim shotdd be smoothed with
a fine file. Emery doth can also be used to advantage for
smoothmgtherim.

The edge of the rim that bears against the tire, just outside
of the bead shotdd be carefully smoothed so that it will not
cut into the tire. When the rim is very rough in the middle,
and the form of the shoe is such that the inner tube bears
against this portion of the rim, a piece of ordinary cotton tape
may be wrapped drcumferentially around the rim so that
the inner tube will bear against it. The end of the tape can
be secured with a small quantity of rubber cement. A pro-
tective paint should be put on the rim to prevent it from rusting.

23. Repla<;ing a Shoe. — ^A new shoe and inner tube
can be put on in two ways. One way is to put the tube inside
the casing first, and then put them both on together; the other
way is to put one bead of the casing on the rim first, and then
put the inner tube in place, as when putting a new tube in a
tire that has had only one side removed from the whed. It
is probably better for the novice to adopt the latter method,
because there is less danger of injuring the inner tube than
when both parts are put on together. Putting the first bead
of the shoe on the rim is generally a simple operation. New
shoes are usually painted inside with talcum or some other
similar substance, so that it may not be necessary to put in

Digitized by

Google

§ 11 AUTOMOBILE TIRES 61

any talcum powder, French chalk, powdered soapstone, or flake
graphite, when putting in the tube.

24. Inserting an Inner Tube. — To insert an inner
tube, first lift the shoe at the opening in the rim through which
the air valve passes in the same manner that it was lifted to
remove the valve of the old tube. Then insert the valve of a
new tube in the hole through the rim, and work in the remainder
of the tube by hand, taking care not to twist it. As soon as the
inner tube has been put in the shoe it should be inflated slightly.

This inflation should be only enough to give the tube its circular
form as nearly as possible. Then force the bead back into the
rim, using the tools in the manner illustrated in Fig. 20. The
tool must not be inserted far enough to catch and pinch the
inner tube. The air valve should be pushed from the wheel
center outwards while forcing the tire in place near it.

The tire can sometimes be replaced more rapidly and easily
by sitting down opposite the wheel and pressing against the
side of the tire at the bottom of the wheel with both feet, at the
same time striking the inner side of the bead of the tire lightly

Digitized by

Google

62 AUTOMOBILE TIRES § 11

with the hammer. As soon as the tire is in place, the valve stem
should be ptished in to see that the tube is not caught under it.

The inner tube can then be inflated
up to about full pressure. The nut
on the valve stem should then be
tightened almost as tight as it is
to be finally, after which the tire
may be fully inflated and then the
nut fully tightened. After the car
has been run a day or two, the nut
should be tightened once more.

Fig. 21 25. Pincliliig Inner Tabes.

If proper care is not exercised in putting a tire in place, an inner
tube is liable to become pinched, and hence injured, or a valve
stem may become caught. Two conditions that may cause
injxiry to an inner tube are shown in Figs. 21 and 22.

In Fig. 21, a part of the inner tube is shown caught under
the edge of the tire on the side that is on the rim, while the
other edge of the tire is free from
the rim. This condition may occur
when the shoe and the inner tube
are put together before placing them
on the wheel rim; or, it may be the
result of improper handling of the
tire tools, especially the prodders,
by means of which the tube may
be pushed under the shoe. It is
not likely to occur, however, if the
tube is properly inflated.

In Fig. 22, a part of the inner
tube is shown pinched imder the
valve stem. The operator should
always pass his hand around the
inner tube after it has been in-
serted and is slightly inflated, in ^^'^
order to straighten it out before putting the second bead of the
tire shoe in place.

Digitized by

Google

§ 11 AUTOMOBILE TIRES 63

HANDLING OF QUICK-DETACHABLE TTRE8

26. Removing the Tire From Rim. — ^Tires mounted on
quick-detachable demountable rims can usually be removed from
the rim before demounting the rim from the wheel as well as
after it has been demoimted. The operation is the same in
each case, except, of course, in the first case the wheel is in a
vertical position while in the second it is generally lying flat.

The method of removing a Firestone quick-detachable tire
without demounting the rim is shown in Figs. 23 to 28. The
wheel being jacked up, first deflate the tire and push the valve

Fig. 23 Fig. 24

stem into the tire as far as it will go in order to release the pres-
sure of the bridge clip. Next, push the side ring inwards,
as shown in Fig. 23, imtil the locking ring a is free to be pried
out and then place a nut 6, or other small object, between the
two rings, thus holding the clincher ring back. The locking
ring can then be pried out of its groove by a screwdriver
inserted in the slot near the end of the ring and removed with
the hands, as shown in Fig. 24.

After the locking ring has been sprung out of its groove, the
side ring can be taken off, as shown in Fig. 25. The tire
shotdd then be removed by swinging it out sidewise. Fig. 26,

Digitized by-

Google

64 AUTOMOBILE TIRES § 11

commencing on the side of the wheel opposite from the valve

and lifting it out at the
valve so as not to injure
the valve stem. After the
tire has been detached from
the rim, the inner tube may-
be removed from the casing.
A quick-detachable tire
is replaced on the rim by
simply reversing the opera-
tions necessary for its re-
moval, care being taken not
to damage the valve stem
in the inner tube.

27* Demounting tlie
^'""^^ Rim From Wlieel.— The

method of demoimting any particular make of demotmtable rim
from the wheel is usually
self-evident and can gen-
erally be ascertained after
a few minutes* examina-
tion. Theworknecessary
to remove a rim, of
course, depends on the
manner in which it is held
on the wheel, but in most
cases it consists in loosen-
ing a nimiber of nuts and
clamps.

Fig. 27 shows the first
operation necessary in
removing a Firestonerim,
with the tire attached,

from the wheel rim. The

six clamp nuts a are Fic. 26

loosened and the clamps b are slipped back so as to dear the rim

and clamping ring. The nuts should be tightened sufficiently

Digitized by

Google

§ 11 AUTOMOBILE TIRES 65

to hold them in that position; or, the clamps may be removed
entirely, if this is con-
sidered more conve-
nient. The rim can
then be lifted from the
wheel as in Fig. 28, care
being taken to have
the tire air valve a at
the top so that it will
be lifted out last. In
many cases the dust
cap must be removed
from the tire air valve,
before the rim can be
taken oflE the wheel.

28. When mount-
ing a demountable rim
on the wheel, turn

the wheel so that the valve hole in the felloe is at the top.
The valve stem may then be inserted and the lower part of the

rim swtmg into place.
The clamps should be
tightened by first giving
each nut one or two turns
I with the wrench and then

going aroimd the wheel
again, tightening up fully
each nut.

ROADSIDE INNER-TUBE
REPAIRS

29. Cement
Patclies. — ^Although it
is not generally advisable

to attempt to repair a

pimcttire of the inner tube on the road, it may be done in case
of necessity. Tire patches for such repairs are obtainable in the

222B— 49

Digitized by

Google

66 AUTOMOBILE TIRES § 11

market, and they are put on with proper repair cement. The
patch should be large enough to extend 1 inch or more beyond
the hole on all sides.

Before putting on a patch, the part of the tire that is to be
patched should be carefully cleaned by rubbing coarse emery
doth or sandpaper over it. Clean gasoline is then used to
dean the tube in this locality. No water or other moisture
should be allowed on the parts to be repaired.

After deaning, the rubber cement is spread thinly over both
the patch and the part of the tube that is to be repaired. The
cement should be allowed to dry until it becomes thick in

consistency, or tacky, as it is
called, which means that it is
very sticky when one's finger is
applied to it. Some cements re-
quire an application of add or
so-called acid-cure solution and
do not have to dry to the same
' extent.

The patch is then laid on, but
care must be taken not to endose
a bubble of air imder it. Prob-
ably as good a way as any is first
to put down one comer of the
Fig. 29 patch while holding the rest up

from the tube, and then to bring the patch down gradually,
as would be done if it were rolled down with a cylindrical
tool. After the patch is in place, it should be hdd down
hard against the tube. This can be done by laying the tube
on a flat surface and then placing a weight on the top of the
patch, or a damp like that shown in Fig. 29 may be used to
hold the patch and the tube together. If the damp is used,
one of its inner faces should be covered with thick f dt or thick
doth so as not to injure the tube. The length of time required
for the cement to set depends on the kind that is used. Ordinary
cement will probably require at least 10 minutes.

A patch put on in this manner will not hold nearly so well
as a properly vulcanized repair, because the heat due to running

Digitized by

Google

§ 11 AUTOMOBILE TIRES 67

the car at high speed will soften the cement and the bending of
the tire will aid in working the patch loose. A patch put on with
cement will hold better in cold weather than in warm weather.

30. No-Cement Patches. — ^A quick repair of a ptmcture
of an inner tube can be made by means of the no-cement patch,
or the self-cementing patch, which can be applied to the tube
without either cement or acid. When using a patch of this
kind, it is only necessary to buff the tube aroimd the pimcture
with emery doth and clean with gasoline. The linen cover
may then be removed from the patch and the gum side moist-
ened with gasoline, after which the patch may be applied to the
tube. It should be pressed down firmly and kept tmder a weight
for a few minutes, when

the tube can again be put
in service. Various sizes
of no-cement patches can
be obtained and the one
best suited for any partic-
ular puncttire used.

31. SeUr-Vulcanlz- *

Ing Rubber and Punc- ^

ture Plugs. — Punc-
tures in inner tubes can also be repaired by making use of
self-vulcanizing, or self-curing, rubber, also sometimes called
self -curing cement. This is a plastic rubber, sold imder various
brand names, such as Michelin Mastic, Goodrich Plastic, U. S.
Heal-a-Cut, etc. It is applied to a puncture by rolling a small
piece between the thumb and forefinger until it takes the
shape of a collar button and then forcing the neck of the
button through the hole in the tube, which has been thoroughly
cleaned aroimd the hole beforehand, and coated with one or
more coats of patching, or self-vulcanizing, cement. Full
directions for the use of the various plastic rubbers are given
on the cans in which they are sold, and these directions should
be followed carefully in each case.

Various forms of inner-tube plugs are also used for repairing
small punctures caused by nails or similar objects. One form

Digitized by

Google

68 AUTOMOBILE TIRES § 11

of punctiire pliig, namely, the Goodrich Permanent Puncture
Plug, is shown in detail and applied to an inner tube in Fig. 30.
It is simply a soft rubber plug a, shaped like a collar button, the
stem of which contains a ball. To mend a pimcture, the neck
of the button is slipped through the hole in the tire, and the
ball prevents the plug from coming out. Several of the plugs
are shown applied to an inner tube.

32. Splicing Inner Tubes. — Sometimes an inner tube
will become so badly worn or ruptured at some point that it is
impossible to repair it in the usual manner by means of patches
and cement. In such a case a repair can be made by removing
the damaged portion of the tube and putting in a new section
by means of splicing. The process of making a splice is more

difficult than that of making an ordinary repair and, hence,
requires the services of an experienced repairman.

33. Splices are of two kinds, namely, the vulcanized splice
and the cold, or acid-cured, splice. The former is made only
in the manuf acttiring plants where the necessary facilities are
at hand, but the latter, or add-ciired, splice can be made with
a few tools by a repairman. In making an acid-cured splice,
the ends of the tube are brought together by means of two
cylinders, called splicers, through which the tube ends extend,
as shown in Fig. 31. The tube ends are turned back over the
ends of the splicers, that on the smaller cylinder a being
doubled back on itself, as shown. The ends of the tube are
tapered with a sharp knife and the surface roughened in the
same manner as when preparing for a patch. The surface of
the tube ends is then cemented and allowed to dry and the
end of the smaller splicer is inserted into the larger one 6 imtil

Digitized by

Google

§ 11 AUTOMOBILE TIRES 69

the end of the tube on the smaller splicer butts against the tube
end on the larger splicer. The curing solution is now applied
and ttie splice immediately made by drawing the end of the
turned back tube on b over the end of the tube on the smaller
splicer a and wrapping tightly with a rubber band. The
rubber band should be kept on 15 or 20 minutes, when the
tube will be ready for service.

34. Leaks in spliced joints in inner tubes are repaired in
accordance with the kind of splice. For instance, if a splice
that has been vulcanized leaks, it can be repaired by vulcaniz-
ing, but an add-cured splice must be taken apart, if possible,
and made over again. If this cannot be done, a new section
must be spliced into the tube, cutting out the part containing
the defective splice.

ROADSIDE REPAIRS TO CASINOS

35. Inside Casing Patches. — If a tire casing is cut
through so as to make a hole of considerable size, the inner
tube may be prevented

from blowing out through
the hole by putting some
kind of a patch on the inside
of the shoe. Patches for
this purpose, known as in-
ner-shoe patches, or Fig. 32
sleeves, can be obtained in many styles. They are usually
made of rubber-filled fabric.

One style of patch is shown in Fig. 32. This patch is com-
posed of several plies of fabric, shaped to fit the different-sized
^^000!00!'SBm^mi!iBs^if^^ casings. The patch is biiilt
^^^^^' -^^^m^ ^p in such a manner that

wM^k^^^ " '"'"iisiB^i^ the outside layer of fabric is

^^^^^^^^^^^^^^^^^^^ smaller than the inside
^^ ^l^^^^^^r^^^^^^^^ layer ; hence, the edge of the
Pig. 33 patch is quite thin, thus

making a smooth joint with the inner tube. This style of
patch is held in place by cement.

Digitized by

Google

70 AUTOMOBILE TIRES § 11

A common form of inside patch is shown in Fig. 33. This
patch is vulcanized and molded to shape and the outside ply

of fabric is made extra wide so that it can be inserted between
the beads of the tire and the clinches of the rim. Other patches
of this form have metal clinches that are attached to each side
of the patch.

A patch in place inside of a casing is shown in*Pig. 34. The
patch a fits between the casing b and the inner tube c; the flaps
on each side help to hold the patch in place.

36. Outside Casing Protectors. — If the cut in the shoe
is so large that there is danger of the shoe tearing open when
inflated, it is advisable to put an outside protector patch
over the tire. Protector patches, also called manchons, made
for this purpose, are on the market. One form of patch is
provided with eyelets and a lace, so that it can be laced into

place, as illustrated in
Fig. 35. This patch is
made of mineral chrome
leather, and the laces are
of rawhide. Probably
the best protector is
made of rubber and
woven fabric, in a man-
ner somewhat similar to the tire shoe. It is also usually held
in place by rawhide laces.

Digitized by

Google

§ 11 AUTOMOBILE TIRES 71

A leather emergency patch that is attached to the clincher
rim or clincher side rings by a patent dip device is shown in
place on a tire in Fig. 36. The patch a is held in place by the
clips b. This patch is manufactured by the 20th Century Tire
Protector Company. In order to secure the most satisfactory
service from outside patches
of the type shown in Fig.
36, it is necessary that the
correct size to fit the tire be
used.

37. A fairly good pro-
tector patch for temporary
use can be made from a sec-
tion of an old tire shoe.
The beads should be cut off

if the old tire is of the clincher type. Holes can then be ptmched
for the lacing.

If the cut in the casing is comparatively small and deep,
as when made by a small piece of glass, it should be probed
with the bltmt end of some small instrument as soon as it is dis-
covered, in order to ascertain whether or not the glass still
remains in it. Frequently, a small piece of glass will embed
itself in the rubber near the surface of the tread as the wheel
passes over it, and then gradually work its way through the
shoe and puncture the inner tube as the wheel travels along
the road. The glass should be removed immediately.

38. Cuts and Blisters. — Cuts of any kind, as well as
blisters, on the tire shoe should be repaired at the earliest
possible moment. If the cut is left open, a sand blister, also
called a mtid boil, is almost certain to form. Although it is
hardly possible to make a durable repair of a cut while on the
road, it can be remedied to some extent. If the cut is small,
it can be temporarily repaired by filling it with rubber cement
and then binding a piece of adhesive tape aroimd the tire over it.
If the cut is rather large and deep, it may be protected by forcing
a piece of rubber patch into it and then cementing this patch
in place. After the cement has set, the patch can be trimmed

Digitized by

Google

AUTOMOBILE TIRES

§11

down smooth with the surface of the tire, and the tire then
wrapped with tire tape. Neither repair is permanent, and
hence a vulcanized repair should be made as soon as possible.

39. The various kinds of plastic rubber mentioned in con-
nection with the repair of inner tubes are also used for filling
small cuts in casings. These rubber preparations are self -dry-
ing and self-curing, and if a cut is filled at night, the tire may
be safely used by morning. These plastic rubber preparations
prevent the exposure of the tire fabric to the disintegrating
eflEects of moisttire and grit, and prevent the formation of
sand blisters.

CARRYING INNER TUBES

40. In order to carry an inner tube so that it will not
be abraded and cut, it should be fully deflated and then closely
folded or rolled and put into a casing, or box. It can be deflated
by rolling it up while the valve insides is removed, replacing
this after the tube has been fully deflated. The successive

Fig. 37

steps of folding a tire into a bimdle are illustrated in Fig. 37.
It is best to cover the valve stem with an ordinary rubber
finger cap, or with a cap of some other material, such as
chamois skin or cloth. Two of the views of the illustration
show the valve stem covered in this manner. An oilcloth bag
makes a suitable covering for the entire tube after it is folded.
The tube should by no means be carried loose among tools,
nor should it be placed where oil or gasoline can get on it.

Digitized by

Google

§11 AUTOMOBILE TIRES 73

VULCANIZED TIRE REPAIRS

PORTABLE VULCANIZEBS

41. The* process of vulcanizing rubber, as already referred
to in connection with patching inner tubes and shoes, consists in
heating the rubber to a temperature sufficient to make it change
from either the gummy or the plastic state, as the composition
may be, to the condition that is found in a new tire casing, or
tube. In other words, in reference to tire work, vulcanization
is the process of heating crude rubber and sulphur in combina-
tion imtil the mass has been brought to a state in which it is
both elastic and dtir-

able.

This process is em-
ployed in both the
manufacttire and re-
pair of automobile
tires, but it is with
the latter only that
the automobile owner,
driver, or repairman is
interested and it alone
will be dealt with here.

In the repair of tires,
a patch on the inner
tube or the rubber re-
inforcement in a cut or blow-out in a casing is vulcanized in
order to make the repair a permanent part of the tire. The
heat for the vulcanizing apparatus, or vulcanizer, is generally
supplied by electricity, steam, or gas. The temperattire to
which the rubber is raised by the vulcanizer should probably
never exceed 250° to 275° F.

42. Various forms of small portable vulcanizers that can be
used by the automobile owner or driver for repairing tires on
the road or in the garage are foimd on the market. One of the

Digitized by

Google

74 AUTOMOBILE TIRES § 11

most popular forms is the electric vulcanizer, an example of
which is the Shaler, type B, shown in Fig. 38. The vulcanizer a
is shown clamped in place on the inner tube b, in which a
pimcture repair is being vulcanized. This vulcanizer may he
operated by either direct or alternating current. The temper-
ature is controlled by a rheostat c, by means of which ths
resistance to the passage of the current can be r^^ulated by
shifting a lever d. The current coming to the vulcanizer passes

through the rheostat and
then through the resistance
coils of the vulcanizer, thus
producing the required tem-
peratture for the vulcanizing
process.

, 43. The vulcanizer shown
is made with one side flat and
the other side concave. The
flat side is to be applied to
inner tubes and the concave
side to tire casings. Casings
may be vulcanized by simply
clamping on the vulcanizer
without removing the tire
from tHe wheel. A thermom-
eter is provided to indicate
the temperatture of the in-
terior of the vulcanizer. The
^^^' ^® advice of the manufacturers

of the apparatus as to what temperature should be used when
vulcanizing should be followed as closely as possible.

44. The first vulcanizers used for preparing rubber were
steam-heated vulcanizers. These were of the large sta-
tionary form and steam was used because the temperature
could be controlled readily by regulating the fire tmder the
boiler. This type of vulcanizer is now used almost exclusively
in repair shops and large garages where a considerable amotmt
of tire repairing is done. Pressure gauges instead of ther-

Digitized by

Google

§ 11 AUTOMOBILE TIRES 75

mometers are used for determining the temperature in the large
vulcanizers, the steam being kept at the pressure corresponding
to the required temperature during the process.

Small steam-heated portable vulcanizers are sometimes used
in the same manner as portable electric vulcanizers for making
small repairs on the road or in the garage. The steam is
generated by means of a gasoline, or alcohol, lamp. Such a
portable vulcanizer is shown in Fig. 39 clamped to a tire casing
in the proper position for
use. The body a of the
vulcanizer contains water
which is heated by the
alcohol lamp 6. A ther-
mometer c, fixed in the body
of the instrument, indicates
the temperature of the
steam. The surface of the
vulcanizer that is to be used
in vulcanizing tire casings Fig. 40

is concave while the opposite surface, or the one to be used on
inner tubes, is fiat.

45. The Adamson vulcanizer, which is of the gasoline-
heated type, is shown in Fig. 40. When vulcanizing an inner
tube, the vulcanizer is laid fiat as shown, gasoline is poured into
the body a and lighted, and the vulcanizing process begins. In
vulcanizing a casing, the vulcanizer is clamped to the casing in
a vertical position with the cup b at the bottom. The gasoline
is then poured into the cup and lighted.

REPAIR OF INNER TUBES AND CASINOS

46. Vulcanizing Inner Tubes. — ^When vulcanizing,
extreme care must be taken not to raise the temperature of the
rubber above a certain maximum. If the rubber is over-
heated, it will become weak, will lose its elasticity, and will be
almost certain to crack when b'^nt short. The temperattire
of the vulcanizer should nattirally be somewhat higher than
that required in the rubber for vulcanizing it, because there is

Digitized by

Google

76 AUTOMOBILE TIRES § 11 .

some loss of heat between the vulcanizer and the tube or casing.
It is advisable to lay an inner tube on a piece of soft material,
such as thick felt, in order that it may have an even contact or
pressure against the vulcanizer, especially when putting on a
large patch.

47. On accoimt of the great danger of injuring the rubber
tube by overheating, a person learning to use a vulcanizer
should experiment on some worthless tubing. He should take
care not to overheat the tubing at the first trials, and should
then increase the temperatiure in successive trials until he finds
the lowest temperattire at which the rubber is vulcanized so that
the patch will hold in place finnly and cannot be pulled oflF by
hand, as when put on with tire cement but not vulcanized. The
length of time required to vulcanize an innet* tube after the
vulcanizer has become thoroughly heated varies with the thick-
ness of both the tube and the patch, but it does not generally
require more than 15 or 20 minutes. It is necessary to bring
the temperature up to a certain n^irk before vulcanizing will
occur. Therefore, there is no need of trying to produce a
successful piece of work by using a low temperature and con-
tintiing the process for a long period. Dealers in automobile
supplies can generally furnish sheet rubber of the proper nature
for making patches that are to be vulcanized.

48. The most important thing in the preparation of an
inner tube for vulcanizing is cleanliness. It is absolutely
necessary that the inner tube that is to be repaired be thoroughly
cleaned of all bloom or talc aroimd the hole or pimcture before
the vulcanizing cement is applied if a good job is desired.
Ordinary rubber cement is useless for making vulcanized repairs ;
regular vulcanizing cement must be used.

When a hole or slit in an inner tube is to be mended by vid-
canization, a piece of prepared rubber, called inner-tube stock,
should be placed inside of the tube, over the hole, and vul-
canized. The tube should be prepared for the job by first
roughening, as far as possible, the inner surface for a space of
from 1 inch to 2 inches around the hole with a piece of emery
clotK or sandpaper. It should then be washed thoroughly by

Digitized by

Google

§ 11 AUTOMOBILE TIRES 77

inserting a piece of doth or a small brush saturated with gaso-
line. A thin coat of vulcanizing cement can now be applied
and allowed to dry for a couple of minutes, or imtil it is quite
sticky, after which a second coat may be put on, when the tube
will be ready for the patch of repair rubber.

A piece of the prepared rubber is cut about J inch larger than
the hole and a piece of paper is stuck to the back or some talc
is put on. The rubber is then inserted in the hole in the tube
with the dean side next to the tube and carefully pressed down,
so that the patch and the tube will be in intimate contact before
vulcanizing. Sometimes a roller tool consisting of a compara-
tively small round-edged roller in the end of a handle is used for
this purpose. The hole or slit can now be filled with a piece of
tjie prepared rubber, and the job will be ready for the vulcanizer.
A piece of waxed paper should be placed between the vulcanizer
and the inner tube in order to prevent their sticking together.

49. An inner tube may be vulcanized in the garage by
hanging it across a board about 6 inches wide that is supported
at only one end and placing the vulcanizer directly on the injured
place and clamping it on. On the road, the tube can be strapped
lengthwise on an inflated tire and the vulcanizer applied. The
exact length of time necessary for vulcanization depends on the
job and on the kind of vulcanizer used; the instructions of
the maker of the vulcanizing apparatus should be most carefully
followed in regard to this.

50. When only a very small puncture in an inner tube is
vulcanized, a small piece of prepared rubber is first inserted in
the hole after the damaged part has been thoroughly deaned
and coated with vulcanizing cement.

Two layers of prepared rubber are then applied over the
pimcture, the first being about | inch larger than the hole and
the second about J inch larger. The vulcanizer can now be
applied after covering the repair with waxed paper.

51. Vulcanizliig Tire Casings. — Small cuts in a tire
casing, if they do not extend clear through the shoe, can usually
be vulcanized without removing the tire from the wheel. The

Digitized by

Google

78 AUTOMOBILE TIRES § 11

cut is prepared for vulcanizing by first washing it out thor-
oughly with gasoline and then roughening the rubber around the
edge with a rasp or wire brush. The surface of the rubber
should then be coated with vulcanizing cement and a piece
of inner-tube stock forced into the cut after the cement has dried.
After bringing the vulcanizer up to the reqiiired temperature,
it can be clamped on the tire and the actual vulcanizing process
begun. Before clamping on the apparatus, however, powdered
talc should be sprinkled on the surface of the tire arotmd the
damaged spot to prevent the vulcanizer from sticking. The
time required for vulcanizing a cut in a casing varies from
30 to 60 minutes, depending on the depth of the cut.

52. In the case of a ragged cut or a tear, the loose rubber
should be cut away, leaving a dean hole in the tread. This
should then be coated with vulcanizing cement and a single
piece of inner-tube stock cut to size inserted, placing over this
two or three layers of tread stock. The prepared rubber,
known as tread stocky and which is suitable for treads, is not
suitable for inner-tube repairs.

53. The size of blow-out that can be repaired successfully
depends on the size of vulcanizer available. The first thing
to do in the repair of a very small blow-out, as in any other tire
repair, is to dean the inside of the tire thoroughly with gasoline
and coarse sandpaper for about 3 inches on each side of the
hole. At least two coats of cement should then be applied and
let dry imtil the gasoline has all evaporated and a smooth sur-
face is obtained on the canvas. A piece of prepared rubber
at least 1 inch larger than the hole should be stuck to the inside
of the casing, and over this three layers of blow-out canvas
applied. The first layer of canvas should be 1 inch larger than
the layer of rubber and each succeeding layer i inch larger all
aroimd than the one before it. After the patches are put in
place, they should be covered with waxed paper and the inner
tube inserted and inflated slightly. The cut on the outside
of the tire can then be prepared like an ordinary cut or tear, and
the vulcanizer applied. The time required for vulcanizing such
a repair is usually from 40 minutes to 1 hour. Large blow-outs

Digitized by

Google

§ 11 AUTOMOBILE TIRES 79

can only be repaired successfully at a regular properly equipped
tire-repair station.

54. A sand blister is prepared for vulcanizing by cutting
half way around the blister with a sharp knife, cutting through
the rubber to the canvas on the side of the blister away from the
tread of the tire. The flap thus formed should be turned back
and pinned down and all dirt removed from imder it. Then
the cut should be cleaned and cemented with vulcanizing cement
as for an ordinary casing cut. Next, a strip of inner-tube stock
as wide as the tire rubber is thick should be stuck on the edge
of the flap and a thin sheet of the same prepared rubber the
exact size of the cavity laid on the canvas and pressed down.
The flap can now be laid back in place and the repair vulcanized,
the time allowed depending on the particular vulcanizer used.
Care should be taken that the hole, through which the dirt
entered, is stopped up.

55. A rim-cut tire shoe can often be repaired in such a
manner by an expert tire repairman that it will give long
service, provided the tire is otherwise good. Repair is made
by vulcanizing strips of fabric over the bead and up from the
bead on both the. inside and the outside of the casing. How-
ever, on account of the increased thickness due to the repair, it
is sometimes difficult to get the bead into the clinch.

56. When a tire shoe has been in use imtil the rubber
tread has worn off enough for the fabric to show in places,
the tire shoe, if the fabric is still in good condition, can often
be repaired to advantage by retreading it.

Two methods of retreading a casing are in use; the pre-
liminary work in both methods consists in removing all the old
tread from the casing, cleaning the exposed fabric of all dirt and
washing it with gasoline, and then applying vulcanizing cement
to the fabric. When this cement has dried to the proper con-
sistency, a so-called tread band, made in the right shape of
rubber in a semivulcanized state, as regularly furnished for
this ptupose by tire manufacturers, is applied.

The casing, in one process, is then enclosed in a cast-iron
mold of the required shape and entirely surroimding the tire,

Digitized by

Google

80 AUTOMOBILE TIRES § 11

a circular spring or other type of metal core being placed inside
the casing. The mold with the enclosed casing is then placed
in a steam kettle and heated by steam imtil the rubber is
vulcanized. A tread produced as just explained is called a
molded tread.

In the other method, an air bag, which is simply a heavy
inner tube made expressly for repair work of this kind, or a
helical spring of the right size and length, is placed inside the
casing, and the semivulcanized tread band is secured to the
shoe by tightly wrapping long strips of muslin around the cas-
ing. The shoe is then placed in a steam kettle and vulcanized
in direct contact with the steam; a tread thus produced is called
a hand-wrapped tread.

Many tire repairmen prefer to build up new treads from
sheet rubber instead of using a semivulcanized tread band.

57. Another method of retreading that is coming into
extensive use also uses tread bands, but instead of being semi-
vulcanized, these are fully vulcanized and are made with various
anti-skid projections. The application of one of these anti-
skid tread bands depends on the cbndition of the old tread.
If this is merely worn down but not torn loose in any way from
the carcass, it is thoroughly cleaned and roughened up, and then
given several coats of a heavy vulcanizing cement, as is also
done to the inside of the tread band, which is applied by stretch-
ing it over the tire. If the tread has torn loose from the car-
cass, all the old tread is removed; the carcass is then thoroughly
cleaned and roughened up, treated to several coats of vulcaniz-
ing cement, and several lawyers of rubber caUed cushion stock
are applied. The tread band, which also has been treated
inside with vulcanizing cement, is then applied to the tire.

An air bag or a helical spring of the correct size and length
is now placed inside the casing ; the tread is seau*ed by wrapping
the casing tightly with muslin strips, and the whole tire is placed
in a steam kettle and then vulcanized.

The application of tread bands to a casing by means of
ordinary rubber cement is a waste of time and money, as they
will come off almost as soon as the tire is put into service; a

Digitized by

Google

• § 11 AUTOMOBILE TIRES 81

tread band must be vulcanized to the tire. The application of
anti-skid tread bands should be only entrusted to a properly
equipped tire-repair station, or to the manufacturer of the tire.

58» The repair of large cuts, blow-outs, and beads, as
well as the retreading of tires, should be entrusted only to a
properly equipped tire-repair shop or to tire manufacturers.
As a general rule, however, manufacturers will repair only
tires of their own make.

223B— 00

Digitized by

Google

Digitized by

Google

INDEX

Nons. — In this volume, each Section is complete in itself and has a number. This number
IS printed at the top of every page of the Section in the headline opposite the page number, and
to distinguish this Section number from the page number, the Section number is preceded by a
section mark (f). In order to find a reference, glance akmg the inside edges of the headlines
until the desired Section number is found, then along the page numbers of that Section until itie
desired page is found. Thus, to find the reference ** Ammeter, |1, p8." turn to the Section
marked |1, then to page 8 of that Sectkio.

Antifreesing mixtures of calcium chloride and

water. Table of freesing point of, f4. p26

mixtures of glycerine, wood alcohol, and

water. Table of freezing point of, f4. p27

mixtures of wood alcohol and water. Table of

freezing point of, H, p25

Antifriction bearings. Classification of, |10, pl4

Application of two-cycle principle, |2, p48

Armature, |8, p3
Actk>n of. 18, p4
and commutator, |8, p7
core and winding. Construction of magneto,

|8,p24
Drum, 18. p4

or keeper. Definition of, (6, pl2
shaft couplings. Magneto, |8, p87
Shuttle-wound, f8, p28
winding. Magneto, f8, p28

Arrangement of four-cylinder four-cycle engine
cylinders. (2, p20
of six-cylinder four-cycle engine cylinders,

|2.p23
of two-cycle engine cylinders, §2, p46
of two-cylinder four-cycle engine cylinders,
|2,pl9

Artificial magnets. Definition of, ftd. pl2

Artillery automobile wheels, fl, p49

Atwater-Kent automatic spark control. f8, p76
-Kent spark generator, (7. pld

Auto trucks, f 1, pi

Automatic engine governors, Types of, f4. p37
inlet valve. 13, p37
spark control, Atwater-Kent, |8, p76
spark control, Bisemann, (8, p69

Automobile bodies. General classification of,
I1.P30
bodies. Open, f 1. p31
bodies. Types of closed, 51. p34
chain, Brampton, fl, p98
Chain-driven. |1, pO
chains, f 1, pOd

A. L. A. M. formula. Table of horsepower by,
|3,p62

A. L. A. M., or S. A. B., horsepower foniittla,
§3,p50

Accelerator, and governor connections. Hand
throttle. 14. pp30. 43
Construction of engine, f4, p36
pedal, (1, p6

Acctmiulators, Definition of. f 6. p21
Lead. ftfi. p3l

Adjustable ball-and-socket joint, f 10. p9
plain bearings. {10, p4

Adjustment, Carbureter, {1. p8

Air-circulating fan, {2, p3
-cooled cylinders, i3. pll
cooling of engine cylinders, f4, p27
pressure for tires. Loads and. |11, p24
pressure for tires, Table of loads and, |ll, p26
-pressure gauge. Starter. |1. p7
-pressure pumps. Gasoline, §3, p48
pump. Hand, f 1. p7

valves. Pump connections to tire, f 11, p37
valves. Tire, §11, pl6

Alternating-current conversion for battery
charging. {6, p40
current. Definition of. §6. plO
-current magneto. Definition of high-fre*
quency, f 8, p92

Ammeter, {1. p8

Ammeters, Definition of. f 7, p28

Ampere-hours. Definition of, f 6, p34
-turns, S8, plO
volt, and ohm. Relation of, |6, p6

Annular ball bearings, f 10. p23
ball bearings, Double-row, f 10, p26
ball bearings. Full-type, §10. p23
ball bearings. Silent type, f 10, p24
ban bearings. Single-row, {10, p26

Antifreezing mixtures for cooling system,
H.P24

222B— 63

Digitized by

Google

INDEX

Automobile. Definition of, §1, pi

-engine cylinder oils. Properties of, |10, p45

frames, Pressed-stcel, §1, pl06

frames. Types of, §1, pl06

frames, Wooden, fl, pl05

Friction-and-chain driven, {1, p9

Friction-driven, Jl. p9

front axles, Parts of. f 1, p56

General assembly of the, f 1, p2

greases. Brands of, (10, p49

Livery, §1, pi

Methods of propelling the, §1, p9

Shaft-driven, {1, p9

springs. Construction and types of, |1, p98

top slip cover. (1, ppO, 37

tops. Canopy, §1, p37

tops. Cape, f 1. p37

wheels, Artillery. §1, p49

wheels. Compression, §1, p49

wheels. Dished. §1. p50

wheels. Spring. (1, p55

wheels. Suspension, 51. p49

wheels. Wire, {I, p52

wheels. Wooden. §1. p49
Auxiliary spark gap. §7, p9
Axle, Definition of dead rear, fl, ppl2, 71

Definition of live rear. (It PP 12, 71

housings. Rear-. (1. p89

Pressed-steel front, 51, p59

Two-speed bevel-gear rear, §9, p72
Axles. Caster steering. (1, p70

Examples of dead rear, (1, p95

Full-floating rear, §1, p82

I-beam front, §1, p57

Parts of automobile front, (1, p56

Plain live rear, §1, p72

Semifloating rear, §1, p7d

Solid front, §1, p57

Three-quarter-floating rear, f 1, pSO

Tubular front. §1. p59

Types of rear. {1. p71

Worm-gear-driven rear, §1, p86

Baldwin detachable roller chain, (1, p97
Ball-and-socket joint. Adjustable, §10, p9

-and-socket joint. Non-adjustable, f 10, p9

-and-socket joint. Self-adjusting, §10, plO

-bearing cages. §10. p28

bearings. Annular. §10. p23

bearings. Double-row annular. §10, p26

bearings. Full-type annular, §10. p23

bearings. Radial. §10, p23

bearings. Silent type annular, §10, p24

bearings. Single-row annular. §10, p28

bearings. Types of, §10. pl5

thrust bearings, §10, p39

Band clutch. Example of contracting, §9, p25

clutch. Example of expanding, §9. p27

Tread, §11, p79
Bar, or rod. Torsion, §1, pl8
Batteries, Capacity of storage, §6, p34

Charging of. §6, p34

Definition of dry, §6, p21

Definition of primary, §6, p21

Definition of secondary, or storage, §6, p21

Definition of wet, §6, p21

Examples of secondary, or storage, §6. p30

when not in use. Recharging of storage, §6, p38
Battery cell. Definition of, §6. p20

charging. Alternating current conversion for,
§6. p40

connections. Arrangements of, §6, p24

connections. Multiple, or parallel, §6, p26

connections. Parallel-series, §6, p28

connections. Series-, §6, p24

Defiriition of electric, §6, p20

Double ignition system with dynamo and,
§8, pl23

Faure type of storage, §6, p32

floated on the line. Storage, §8, pl6

Laying up of storage, §6. p39

Plants type of storage, §6, p32

Reversed connections in parallel, §6, p26

Reversed connections in series, §6, p26

•switch connections, §6, p29

switches, §7, p21
Bearing, Bower roller, §10, pl8

cages, Ball-, §10, p28

Grant roller, §10, p22

High-duty Hyatt roller, §10, pl7

New Departure double-row ball, §10, p38

Norma roller, §10, pl7

Standard Hyatt roller. §10, pl6

Standard roller, §10. p20 ^

Timken roller. §10, p20
Bearings, Adjustable plain, §10, p4

Annular ball, §10, p23

Ball thrust, §10, p30

Classification of antifriction, §10, pl4

Cup-and-cone ball, §10, p35

Definition of plain, §10, pi

Double-row annular ball, §10, p26

Full-type annular ball, §10, p23

Materials for plain. §10, pl2

Non-adjustable plain. §10, p2

Plain thrust, §10, pll

Radax ball, §10. p37

Radial-and-thrust ball, §10, p95

Radial ball, §10, p23

Silent type annular ball, §10, p24

Single-row axmular ball, §10, p26

Straight roller, §10. pl5

Swivel, §10, p7

Digitized by

Google

INDEX

Bearings. Tables of identification numbers of
ball. §10. P30

Tapered roller, §10. p20

Three-point ball, f 10. p35

Types of ball. JlO, pl5

Types of roller, §10. pl4
Beau de Rochas cycle, §2, p7
Berline bo4y. §1. p35
Bevel-gear differential. Example of, §1, p74

-gear rear axle. Two-speed, §9, p72

-pinion-and-sector steering gear, §9, p96
Blisters, Repair of tire cuts and. §11, p71

Tire. §11, p60
Block-and-truxmion type of universal joint,

§9. p78
Blocks, Cylinder, §2, p3
Blow-out, Definition of, §11, p62
Board, Cowl, §1, p7

Heel, §1. p5

Toe, §1, p5
Boards, Running, §1, p9
Bodies, General classification of automobile,
§1.I>30 .

Open automobile, §1, p31

Types of closed automobile, §1, p34
Body, Berline, §1, p35

Brougham, §1, p3d

Deznilimotisine, §1, p36

Taxicab, §1, p36

Touring coach, §1, p36
Bosch double-ignition system. §8, pi 18

double-ignition system. Wiring diagram for,
§S. pl21

dual magneto. Construction of, §8, pi 10

dual system. Wiring diagram for, §8, pill

single high-tension magneto, §8, plOO

single system. Wiring diagram for, §8, pl03
Bower roller bearing, §10, pl8
Box, Definition of, §10, pi
Brake. Clutch, §9, pp7, 34

Emergency, §9, p97

equalizers, §9, pl04

Hinged contracting, §9, p99

Service. §9. p97

Toggle expanding, §9, p99

Transmission, §9, pl03
Brakes. Expanding and contracting, §9, p97
Brampton automobile chain, §1, j)9S
Breaker strips, §11, p4
Breathers, Crank-case, §3. p21
Bridge clips, §11. p20
Broken, or open, circuit, §6, plO
Brougham body, §1, p36
Busses, Motor. §1, pi

C
Cages, Ball-bearing, §10, p28
Cam-lever, Valve, §3, p44

Cam lobes, §2, p5

-shaft. Example of valve, §3, p40

-shaft. Methods of driving valve, §3, p46

-shafts. Valve. §2, p5
Cams, Examples of valve, §3, p40

Valve, §2. p5
Canopy automobile tops, §1, p37
Capacity of storage batteries. §6, p34
Cape automobile tops, §1, p37
Car, Double-chain drive, §1, pl2

Livery, §1, pi

Motor, §1, pi

Side-chain-drive, §1, pl2

Single-chain-drive, §1, pl2
Carbtu-eter, §1, p7

adjustment, §1, p8
Care of rims, §11, p60
%arB, Delivery, §1, pi

Touring, §1. p33
Casing from rim. Removing clincher, §11, p59

or shoe. Tire, §11, p3

patches. Inside, §11, p69

protectors. Outside, §11, p70
Casings, Vulcanizing tite, §11, p77
Caster steering axles, §1, p70

steering. Methods of, §1. p69
Cell, Construction of voltaic. §6, p9

Definition of battery, §6, p20

Resistance and voltage of a. §6, pll
Cells, Example of dry, §0, p23

Uses of wet. §6. p22
Cellular-radiator construction, §4, pl4
Cement, Self-curing, §11, p67

tire patches, §11, p65
Center, Crank dead, §2, p6

Inner, or upper, dead, §2, p6

Outer, or lower, dead, §2, p6
Centrifugal engine governors, Example of,
§4,p41

force. Definition of, §8, p69

speedometer, §1, pp41, 42

water-circulating pump, §4, p20
Chain, Baldwin detachable roller, §1, p97

Brampton automobile, §1. p98

-drive driving-mechanism arrangements,
§1.P28

-driven automobile, §1, p9
Chains, Automobile, §1, p96

Improperly fitted tire, §11, p60

Tire. §11, p42
Chamber, Combustion, §2, p6
Change-speed gears. Classes of, §9, p37

-speed gears, Classification of sliding, §9, p38

-speed gears, or transmission. Purpose of,
§9.p37

-speed gears. Principle of operation of plan-
etary, §9, p58

Digitized by

Google

INDEX

Change-Speed lever, f 1. p6

-speed mechanism, Potar-speed sdective,
59.P47
Charge-and-discharge system of ignition. Con-
denser, (8. p41

Definition of. (2, p6

Definition of electrical, §6, pi
Charging, Alternating current conversion for
battery, |6. p40

of storage batteries, f 6, p34
Chassis, Definition of, (1, p2

parts. Nomenclature of typical, Sl> pl2
Circuit, Closed or complete, |6, plO

Definition of electric, ^, plO

Divided. §6. plO

External. ^, plO

Grotmded, (6, plO

Internal, ^, plO

Magnetic, i6, pl4

Open or broken, ^, plO

Parallel, or multiple, ^, plO
Circulating pump. Methods of driving, i3,'p45
Circumferentially split rims, f 11, pl5
Clincher casing from rimt Removing, fll, p59

tires. Quick-detachable, (11, pp3, 5

tires. Regular, fll, p3
Clips, Bridge, fll, p20

Spring recoil. {1. plOl
Closed automobile bodies. Types of, (1, p34

or complete circuit, (6, plO
Clutch brake, $9. p7

brakes, (9, p34

Definition of cone, |9, p2

Definition of contracting, (9, p3

Definition of disk, (9, p2

Definition of expanding, §9, p3

Dragging of, (9. pl6

engagements. Devices for securing smooth,
S9, pl2

Engine, (2, p3

Example of contracting band, (9, p25

Example of expanding band, (9, p27

facing. Methods of securing cone-, §9, pll

Interlocking device for speed-change gears
and. S9. p57

Multiple-spring cone, (9, p6

Ordinary form of cone, J9, p3

pedal, §1, p5

-pedal connections, §9. i>30

pedals. Adjustable, (9, p31

Three-plate, §9, pl9
Clutches, Cork-insert, (9, pl3

Dry-plate, $9. pld

Priction materials for, (9, p35

Principle of multiple-disk, (9. pl4

Purpose of friction, §9, pi

Reversed cone, $9, p9

Clutches running in oil, §9, pplOt 31
Cocks, Gauge, flO, p85

Coil. Definition of magnetising, or exciting,
(6, pie

Example of four-terminal induction, 16, p50

Example of vibrator induction, §6, p47

High-tension, §6, p44

Low- tension. |6. p44

Primary, 16, p44

Secondary, (6, p44

Spark, il, p7

Transformer, or non-vibrator, induction,
ft6.-p45
• Two spark plugs with one, |7, p42
Coils, Field magnets and, (8, p9

Inductance, or kick, (6, x>41

Induction, (6, p43
Cold test of oa, SlO. p47
Colunu, Steering, fl. p5
Combined splash-and-pressure-feed lubrication
system. Example of, (10, p73

splash-and-pressure feed lubrication systems,
, (10, p53

timer and distributor. (7, pl5
Combustion chamber, (2, p6
Commercial vehicles, (1. pi
Commutator, Armature and, (8, p7
Commutators, Distributors, or secondary,
(7. pl2

Timers, or primary, (7, plO
Comi^ete, or closed, circuit, (6. plO
Compound field winding. Definition of. (8, pl2
Compression automobile wheels, (1. p49

space, (2, p6

stroke, (2, pl2
Condenser charge-and-dischaige ssrstem of
ignition, (8, p41

Electric, (6, p45

Grounding the, (7, p42
Conductors and insulators. (6, p2
Cone clutch, Definition of, (9. p2

-clutch facing. Method of securing. (9, pll

clutch. Multiple-spring, (9. p6

clutch. Ordinary form of, (9, p3

clutches. Reversed. (9, p9
Connecting-rods, Engine, (3, p34; (2, p3
Connection, Grounded, (6, plO
Connections, Arrangement of steering, (9. p86

Arrangements of battery, (6, p24

Battery-switch, (6, p29

Qutch-pedal, (9, p30

in parallel battery. Reversed, (6. p27

in series battery. Reversed, (6. p26

Multiple, or parallel, battery, (6, p26

Parallel-series battery. (6, p28

Radiator, (4, pl8

Series-battery, (6, p24

Digitized by

Google

INDEX

xiu

Connections, Steering, §1, p66

Voltammeter. (7. p33
Constant-mesh gears, (9, p47
Contact igniter, Low-tension, 57, pi

system of ignition, {7. ppl, 34
Contracting and expanding brakes, (9, p97

band clutch. Example of, §9. p25

brake. Hinged, $9, p99

clutch. Definition of, 59, p3
Control, Atwater-Kent automatic spark, |8, p75

Eisemann automatic spark, fS, p69

Franklin governor spark, §8, p71

Methods of spark-time, §8. p64

Multiple-ball coupling spark. §8. p74

Operation of hand spark. (8. p65

Principle of operation of governor spark.
(8, p68

Spark, §1, p6
Conversion for battery charging. Alternating-
current, 56, p40
Converters, or rectifiers, 56, p40
Cooling system, Antifreezing mixtures for.
54. p24

system. Draining the, 54, p27

system. Engine, 54, pi

system. Forced-circulation, 54, p2

systems, Thermo-siphon, 54. p5
Core, Definition of radiator. 54. plS

Electromagnet. 56, pl6
Cork-insert clutches, 59, pl3
Countershaft, or jack-shaft, 59. p38
Coup6, 51. P34

Coupling spark control. Multiple-ball, 58, p74
Couplings, Magneto armature shaft, 5S, p87

Magneto-shaft, 59, p81
Cowl board, 51. p7
Crank-case breathers, 53. p21 ; 52, p28

•case. Engine, 52. p3

-cases, General construction of, 53. pl5

-cases. Typical, 53, pl6

dead center. 52, p6

end of cylinder. 52, p6

-handle, 51. p8

-pin, 52, p5

-shaft. Engine, 52, p3

-shafts. Engine, 53, p36

Starting, 51, p8
Cranks. Engine. 52, p3
Cross type of universal joint, 59, p76
Cup-and-cone ball bearings, 510, p36
Cups, Grease, 510, pS9

Oil, 510. p88 '
Current. Definition of alternating, 56, plO

Definition of direct, 56. plO

Definition of electric. 56. p2

frequency. 58. p23

Graphic representation of magneto. 58. p21

Current, Intermpted primary magneto. 58, p36

Interrupted short drcuit of ^primary mag-
neto, 58, p40

interrupter. Vibrator, trembler, or, 56, p49

Primary, 56. p44

Secondary, 56. p44

Short-circuited primary magneto, 58, p39
Currents, Eddy, 58, pp7, 27
Cushion stock, 511. p80

tires. 511, pi
CuVout valves. Muffler. 54. pp30, 33
Cuts and blisters. Repair of tire, 51 1> p71
Cycle. Beau de Rochas. 52. p7

Definition of gasolin»-engine, 52. p7

Otto. 52. p7
Cylinder blocks. 52, p3

Crank end of, 52. p6

Head end of, 52, p6

he.id. Valves in, 53. p45

jacket spaces. 52. p3

L-head type of engine. 53, p3

oils, Properties of auiomobile-engine, 510. p45

priming cups. 53, p48

scavenging, 52, p9

T-head type of engine, 53. pi

Valve-in-the-head type of engine, 53. p4
Cylinders. Air-cooled, 53, pll

Air cooling of engine, 54. p27

Arrangement of four-cylinder four-cycle
engine, 52. p20

Arrangement of six-cylinder four-cycle en-
gine. 52. p23

Arrangement of two-cycle engine, 52. p46

Arrangement of two-cylinder four-cycle en-
gine. 52. pl9

cast en bloc. 52. p20

cast en bloc. Four-cylinder engine with.

52. p33

cast en bloc. Six-cylinder engine with. 52. p40

cast in pairs and in threes. Six-cylinder en-
gine with. 52. p38

cast in pairs. Four-cylinder engine with.
52.P29

cast separately. Four-cylinder engine with.
^ 52. p26

cast separately. Six-cylinder engine with.
52.P36

Offset, 52. p29

Twin. 52. p20

with integral heads and jackets. Water-
jacketed. 53. pi

with separate heads. Water- jacketed, 53. p7

with separate water-jackets. Water- jacketed,

53. plO

D
Dashboard, 51. p7
Dead center. Crank, 52, p6

Digitized by

Google

XIV

INDEX

Dead center. Inner, or tipper, |2, p6

center, Outer, or lower, {2. p6

rear axle. Definition c^, |1, ppl2, 71

rear axles, Example of, f 1, p95
Delivery cars, (1* pl

wagons, (1, pi
Demilimousine body, |1. p36
Demountable and quick-detachable rims.
Definitions of, fll. p9

rim, Bolted-on, (11, plO

rims. Types of, §11, p9
Density. Magnetic, $6. pl4
Depolarization, Definition of, ft6, p22
Detachable tire protectors, (11, x>40

-tread tire, 511, p7
Device, Vibrator impact, |6, p49
Devices for securing smooth clutch engage-
ments. §9, pl2
Differential, Example of bevel-gear, (1. p74

Spur-gear, fl, p7d; 19. p84
Direct current, Definition of, ft6, plO

-current generator. Self-excited, §8, pl3

-current generators, |8, pi

drive. 59. p38
Di^ed automobile wheels, |1, p50
Disk clutch. Definition of, |9. p2

clutches. Principle of multiple-, (9, pl4
Distributor, Combined timer and. |7, pl5
Distributors, or secondary coounutators, S7,pl2
Divided circuit, (6. plO
Double-acting engines, (2, pi

•chain drive car, $1. pl2

ignition system, Bosch, |8, pi 18

ignition system. Definition of, |8, pi 17

ignition system. Wiring diagram for Bosch,
§8. pl21

ignition system with dynamo and battery,
&8.P123

•opposed engine, (2, pl9

-tube tires. Classification of, (11, p2
Dragging of clutch, (9. pl6
Drain, Radiator. §4. Pl8
Draining the cooling system, f4, p27
Drive. Direct, §9. p38

Worm-bevel, §9, p85
Driver's seat, (1, i>5

Driving-mechanism arrangements. Chain-drive,
I1.P28

-mechanism arrangements. Shaft-drive,
51. Pl4

Tire wear due to improper, 511. p49
Driun armature. 58. p4
Dry batteries. Definition of. 56. p21

cells. Example of. 5^. p23

-plate clutches, 59. pl6
Dual-ignition system. Definition of. 58. pl04

-ignition systems, Low-tension, 57. p45

Dual-ignition sytXanSt Low-tension magneto,
58.P42
magneto, Construction of Bosch, 5^, pi 10
magneto. Construction of Eisemann, 58, pi 13
magneto system. High-tension, 58, pi 10
magneto system. Low-tension. 58, pl04
system of ignition. Principle of operation of

Splitdorf, 58, pl05
system. Wiring diagram for Bosch, 58, pill
system. Wiring diagram for Eisemann,
58. pll5

Dummy journal, 53, p36

Dunlop tire, 511. PP3. 7

Duplex ignition sjrstem. 58. pl27

Dynamo. 51. p8
and battery. Double ignition system with,

58. pl23
-electric generator. Shunt- wound, 58. pH
-electric generators, 5^. pi
-electric generators. Self-exdted. 58. pll
-electric generators. Series-wound, 5^, pll

Eddy currents, 58. pp7, 27

Eisemann automatic spark control, §8. p60

dual magneto. Construction of, §8. pi 13

dual system. Wiring diagram for, 58, pi 15
Electric battery. Definition of, 56. p20

circuit. Definition of, 56. plO

condenser, 56, p45

current. Definition of, 56. p2

gear-shifting mechanism, 59, p64

generator, 52. p3

generator. Essential parts of an, (8, p3

potential. Definition of, 56, p4

spark. Methods of producing, 58, p63

8peed(»neters, 51. p42

vulcanizer. Portable. 511. p74
Electrical charge. Definition of, 56, pi

ground, 56. plO

resistance, 56. p4
Electricity, Definition of, 56, pi
Electrode, Negative terminal or, 56, plO

Positive terminal or. 56, plO
Electrodjmamics, Definition of, 56, p2
Electrolyte. Definition of. f 6, p9
Electrotnagnet core. 56. plO

Definition of. 56. pl6

Horseshoe. 56. pl8

Yoke of. 56. pl8
Electromagnetic induction, 56, pl8

induction, Law of, 58. pl9
JSlectromotive force. Definition of, 56, p5

force. Direction of induced, 58, p2

force. Intensity of. 58. p3

force. Methods of producing, 56, p6
Electrostatics, Definition of, 56. p2

Digitized by

Google

INDEX

Elementaxy magneto generator, f8, p23
Elliott steering knuclde. (1, pp57. 62

steering knuckle. Reversed, |1, pp67, 64
Emergency brake. $9, p97

-brake lever. (1, p6
En bloc. Cylinders cast, (2, p20
End. Adjustable yoke. (10, p3

Plain yoke, (10. p2
Engine accelerator. Construction of, |4* p36

clutch, S2. p3

connecting-rods, §2. p3; (3, i>34

cooling system, (4, pi

crank-case, (2. i>3

crank-shaft, (2, p3

crank-shafts, (3, p35

cranks. 12. p3

cylinder, L-head type of, |3, p3

cylinder, T-head type of, (3, pi

cylinder, Valve-in-the-head type of, |3, p4

cylinders. Air-cooling of, f4. p27

cylinders. Arrangement of two-cycle, f2, p46

Definition of four-cycle. (2, p8

Definition of internal-combustion, (2, pi

Definition of two-cycle, (2. p8

Double-opposed, (2, pl9

Example of three-cylinder two-cyde,
I2.P48

Example of two-cylinder two-cycle, (2, p48

flywheel. (2. p3

General construction and control of four-
cycle, (2. 18p

governing by hand or foot. (4, p34

governors. Example of centrifugal, {4, p41

governors. Example of hydraulic. {4, p38

governors. Types of automatic, §4, p37

hood, fl, p8

hood ledge, f4, pl3

Influence of spark intensity on starting,
(8, p81

lubrication systems. Classification of, flO, i>50

Operation of four-cycle. (2, plO

Operation of three-port two-cycle, |2, pl7

Operation of two-port two-cycle. |2, pl3

pistons. Construction of. (3, p27

suspension. Three-point and four-point,
§2,p44

Valveless two-cyde, §2, pl7

with cylinders cast en bloc. Pour-cylinder,
(2, p33

with cylinders cast en bloc. Six-cylinder,
52.P40

with cylinders cast in pairs and in threes. Six-
cylinder, §2, p38

with cylinders cast in pairs. Four-cylinder,
(2, p20

with cylinders cast separately, Pour-cylinder,
§2,p26

Engine with cylinders cast separatdy. Six-
cylinder, (2, p36
Engines, Double-acting, (2, pi

Horizontal, f2, p7

Non-i>oppet- valve, (2, pl3

Order of explosions of four-cylinder four-
cycle, |2, p21

order of explosions of six-cylinder. (2. p24

order of explosions of two-cycle. 12, p40

Poppet-valve, $2, pl3

Single-acting, §2, pi

Types of four-cylinder four-cyde, (2, p26

Vertical, §2, p7
Epicyclic-gear train. (0, p58
Equalizers, Brake. fO, pl04
Exciting coil. Definition of magnetizing, or,

|6,pl6
Exhaust gases, (2, p7

manifolds, S3, p26

mufflers. Purpose and construction of, |4, p30

port, S2, p5

stroke, (2, pl3

valve, (2, p5
Expanding and contracting brakes. |9, p97

band dutch. Example of, (9, p27

brake. Toggle, (9. p99

dutch, Definition of. (0. p3
Explosions of four-cylinder four-cycle engines.
Order of. (2, p2X

of six-cylinder engines. Order of, 12. p24

of two-cyde engines. Order of, |2, p46
External circuit, (6, plO

Facing, Methods of securing cone-clutch,

I9.P11
Factors affecting spark intensity, (8, p79
Failure. Causes of tire, $11. p45
Pan, Air-circulating, (2, p3
Paur6 type of storage battery, J6, p32
Fenders, (1, p9
Pidd magnet, |8, p3

Magnetic, (6. pl4

magnets and coils. 18. p9

magnets. Magneto. f8. p28

magnets. Rocking. %S, p83

winding. Definition of compound, (8, pl2
Fire point, or test, of oil, (10, p47
First, or low, speed. |9, p40
Fixed spark, J8, pp64, 78
Flash point, or test, of oil. §10. p47
Flexible- joint drive, Speedometer, §1, p47
Float oil-levd gauge. §10. p85
Floated on the line. Storage battery, §8, pl6
Fluid-pressure si>eedometers, (1, p42

shock absorbers, §1, pl03
Flywhed, Engine. §2, p3

Digitized by

Google

XVI

INDEX

Folding top. |1. pO
Foot-throttle, U. p6
Force. Definition of centrifugal, (8, p69
Magnetic lines of, f6, pl4
Magnetizing, or magnetomotive, |8, plO
pumps. Plunger, JlO, pp76, 77
Forced-drcxxlation cooling system. §4. p2
Ford high-frequency magneto. Construction of,
fS. p92
magneto. "Wiring diagram for, f8, p94
Pork, Tire. 511. p55
Forks. Example of shifter. §9. p39
Formula, A. L. A. M., or S. A. E., horsepower,

§3.p50
Forward, or outward, stroke. §2, p6
Four-cycle engine cylinders. Arrangement of
four-cylinder, f 2. p20
-cycle engine cylinders. Arrangement of sii-

cylinder. {2. p23
-cycle engine cylinders, Arrangement of two-
cylinder. 12. pl9
-cycle engine. Definition of, §2, p8
-cycle engine. General construction and con-
trol of, (2. pl8
•cycle engine. Operation of. (2, plO
•cycle engines. Order of explosions of four-
cylinder. S2. p21
•cycle engines, Tyi>es of four-cylinder. §2. p26
-cylinder engine with cylinders cast en bloc,

S2,p33
-cylinder engine with cylinders cast in pairs,

.cylinder, §2. p29
•cylinder engine with cylinders cast sep-
arately, f 2, p26
-cylinder jump-spark ignition with bat-
teries, (7. p44
•point engine suq>ension, §2, p44
-point timer. Example of, f7, p44
-speed selective change-speed mechanism,

|9.p47
-terminal induction coil. Example of, §6, p50
Frame, §1. p9

Frames. Pressed-steel automobile, f 1, pl06
Types of automobile, f 1, pl05
Underslung. (1. pl07
Wooden automobile. §1. pl05
Franklin governor spark control, f 8, p71
Freezing point of antifreezing mixtures of cal-
cium chloride and water. Table of, H> p26
point of antifreezing mixtures of glycerine,
wood alcohol, and water. Table of, {4, p27
point of antifreezing mixtures of wood alcohol
and water. Table of. (4. p25
Frequency. Current. §8. p23
Friction-and-chain driven automobile, (1, pO
clutches. Purpose of, (9. pi
Definition of, (10, p43

Friction-driven automobile, (1. p9

-gear transmission, §9, p62

materials for clutdies, (9, p35

shock absorbers, |1. pl02
Front axle, Pressed-steel, (1, p59

axles. I-beam, |1, p57

axles. Parts of automobile, fl, p56

axles. Solid, fl, p57

axles. Tubular, §1, p50

road wheels, fl, p5

Storm, fl, p38

wheels. Mounting, |1, p68
Full-floating rear axles. (1, p82

Gap, Auxiliary spark, |7, p9

Gases, Exhaust, §2. p7

Gasoline air-pressure pumps, §3, p38

-engine cycle. Definition of, (2, p7

vtilcanizer. Portable, |11, p75
Gauge cocks, flO. p85

Float oil-level, flO, p85

Starter air-pressure, fl, p7

Transferring oil, |10, p86
Gauges, Glass oil, flO, p85

OU-level, 510. p85

Tire pressure. §11, p39

Tire pumps fitted with, (11, p36
Gear, Bevd-pinion-and-sector steering, f9, pQ5

oil-pumps, (10, pp75, 77

or reverse. Purpose of reversing, (9, p37

Planetary tyi>e of steering. (9. p96

Screw-and-nut type of steering. (9, p02

-shift lever, (1, p6

-shifting mechanism. Electric, (9, p64

-shifting mechanism. Hand, (9, p48

-shifting mechanism. Pneumatic, (9, p70

-shifting mechanism, Sliding-shaft type of.
(9,p50

-shifting mechanism. Swinging-lever type of,
(9, p52

water-circulating pump, (4, p22

"Worm-and-sector steering, (9, p91

Worm-and-worm-whed steering. (9, p89
Gears, Classes of change-speed, (9, p37

Classification of sliding change-speed, §9, pSS

Classification of steering, (9. p88

Constant-me^, (9, p47

or transmission. Purpose of diange-^>eed«
(9,p37
Generator, Atwater-Kent spaik, (7, pl6

Electric, (2, p3

Elementary magneto, (8, p23

Essential parts of an dectric, (8, p3

Self-exdted, direct-current. (8. pl3

Shunt- wound, dynamo-dectric, (8, pll

Theory of magneto, (8, pl9

Digitized by

Google

INDEX

xvu

Generators, Classification of ignition. |8. pi

Direct-current, 48, pi

Dynamo-electric. §8, pi

Magneto-electric. $8, pi

Self -excited dimamo-electric, iS, pll

Series-wound dynamo-electric, (8, pll
Glass oil gauges, |10, p85

Sight-feed, (1. p8
Glasses, Oil sight-feed, (10, p87
Governing by hand or foot, Engine, |4, p34
Governor connections. Hand throttle, accelera-
tor, and, f4. pp30. 43

spark control, Franklin, f8, p71

spark control. Principle of operation of,
S8,p68
Governors, Example of centrifugal engine,
Rp41

Example of hydraulic engine, Ht p38

Types of automatic engine, §4, p37
Grade meter, (1, p41
Grant roller bearing, (10, p22
Graphite, $10, p44
Grease, flO, p44

cups, SlO. p89
Greases, Brands of automobile, |10, p49
Ground. Electrical. (6. plO
Grounded circuit. (6. plO

connection, (6, plO
Grounding the condenser. (7, p42

Hand air pump, §1, p7

gear-shifting mechanism, (9, p48
•operated tire ptunps. Classes of, §11, p27
spark-control construction. Example of,

§8, p66
spark control. Operation of, S8, p65
throttle, accelerator, and governor connec-
tions, §4, pp39, 43

Head, Cylinder, (2, p6
end of cylinder, |2, p6

Headlight. Electric. (1, p7

Heel board, fl. p5

High-frequency alternating-current magneto.
Definition of, (8, p92
-frequency magneto. Construction of Ford,

f8,pg2
-pressure lubrication systems, |10, p71
speed. Third, or. (9. pll
-tension coil, §6, p44
-tension dual magneto systems. §8, pi 10
-tension ignition system. Single-spark, $7, p36
-tension magneto, Bosdh single, §8, plOO
-tension magneto,Construction of Mea,S8, p96
-tension magneto. Definition of, (8, p45
-tension magneto with double armature
winding, §8, p49

High-tension magneto with single armature
winding, (8, p45
-tension magneto with stationary armature,

18, p55
-tension magneto with stationary winding,

|8.p60
-tension single magneto system, (8, pp91, 95
-tension system of ignition. Jump-spark, or,
§7, ppl, 36
Hinged contracting brake, §9, p99
Honeycomb radiators. (4. pld
Hood. Engine. (1, p8

ledge. Engine. f4, pl3
Horizontal engines, (2, p7

transmission. Definition of, (9, p38
Horn, Signal, fl, p7

Horsepower by A. L. A. M. formula. Table of,
S3. p52
formula, A. L. A. M., or S. A. E.. §3, p50
rating, f3, p50
Horseshoe electromagnet, (6, pl8
Housings. Rear-axle, (1. pd9
Hoyt voltammeters. §7, p30
Hyatt roller bearing, High-duty, f 10, pl7

roller bearing. Standard, §10* plO
Hydraulic engine governors. Example of,
H.P38

I
I-beam front axles, (1, p57
Identification numbers of ball bearings. Tables

of, SIO, p30
Igniter, Low-tension contact, |7, pl
Magnetic make-and-break, (7, p4
Ignition, Condenser charge-and-discharge sys-
tem of, S8, p41
Contact system of, (7, ppl, 34
Jump-spark, or high-tension, system of,

J7, ppl, 36
Low-tension system of, (7, ppl, 34
Make-and-break system of. (7, ppl, 34
Principle of operation of Splitdorf dual sys-
tem of, §8, pl05
system, Bosch double, §8, pll8
system. Definition of double, §8, pll7
system. Definition of dual, §8, pl04
system. Definition of two-point magneto.

S8, pl24
system. Duplex, §8, pl27
system. Individual-coil, jump-spark, §7, p44
system. Single-spark, high-tension, (7, p36
system. Wiring diagram for Bosch double,

i8. pl21
system. Wiring diagram for two-point,

§8, pl25
system with djmamo and battery. Double,

i8, pl23
system with vibrator coil. Jump-spark, (7, p39

Digitized by

Google

xvm

INDEX

Ignition systems. Classification of single mag-
neto. 18. p91
systems, Low-tension, dual-. 57, p45
systems. Low-tension magneto dual. §8. p42
Touch-spark system of. {7, ppl, 34
Two-cylinder-cngine, 57. p43
Wipe-spark system of. 57. ppl. 34
with batteries. Four-cylinder, jump-spark.
57.P44

Impact device. Vibrator. §6, p49

Individual-coil jump-spark ignition system,

57, p44

Induced electromotive force, Direction of,

58, p2

Inductance, or kick, coils, 58. p41
Induction coil. Example of four- terminal,
56. p50

coil. Example of vibrator. 56, p47

coil. Transformer, or non-vibrator, 56, p46

coils, 56. p43

Electromagnetic. 56. pl8

in revolving loop. 58. p20

Law of electromagnetic, 58, pl9

Self-. 56. p41
Inductor type of magneto. 58. p31
Inflating tires, Methods of, 511. 25
Inflation from storage tanks. Tire. 5H. p36
Inlet manifolds, 53, p24

port, 52. p5

valve. 52. p5

valve. Automatic, 53. p37
Inner, or upper, dead center. 52, p6

-shoe patches. 511 > p69

tube. 511. P3

tube. Chafing of. 511. p49

tube. Inserting an, 511. p61

tube. Removing. 511. p56

tubes. Carrying, 511. p72

tubes. Pinching, 5ll. p62

tubes. Splicing. 511. p68

tubes, Vulcanizing. 511. p75
Innerliners. Tire. 511. p4 1
Inside casing patches. 511. p69
Insulated wires, 57, p26
Insulators and conductors. 56. p2
Intensity. Factors affecting spark. 58, p79

of electromotive force. 58. p3
Interlocking device for speed-change gears and

clutch, 59. P57
Intermediate, speed. Second, or, 59. p40
Internal circuit, 56. plO

-combustion engine. Definition of, 52, pi
Interrupted primary magneto current. 58. p36

short circuit of primary magneto current.
58. p40
Interrupter. Vibrator, trembler, or current,
56, p49

Inward, stroke, Return, or, 52. p6
Irons. Tire, 511, p53

Jack-shaft. Countershaft, or, 59, p38
Jacket spaces. Cylinder, 52. p3
Joint, Adjustable ball-And-socket. 510. p9
Block-and-tnmnion type of universal. 59, p78
Cross type of universal. 59, p76
Non-adjustable ball-and-socket. 510. p9
Ring type of universal, 59. p7S
Roller type of universal, 59, p78
Self-adjusting ball-and-eocket, 510, plO
Slip sleeve of universal, 59. p76
Universal, 51. Pl6
Journal, Definition of, 510. pi

Dummy. 53. p36
Jump-si>ark ignition 83rstem. Individual-coil,
|7,p44
•spark ignition 83rstem with vibrator coil.

57.P39
-«park ignition with batteries. Four-cylinder.

57.P44
-spark or high-tension, system of ignition,
57. ppl, 36

Keeper, Definition of armature, or, 56, pl2
Kick coils. Inductance, or, 56. p41

L-head tirpe of engine cylinder, 53. p3

Lamp. Tail-, 51, p8

Lamps. Side. 51. p8

Landaulet. 51. p36

Law of electromagnetic induction, 58. plO

Ohm's, 56, p7
Laying up of storage battery, 56, p39
Lead accumulators. 56. p31
Lemoine steering knuckle, 51. pp57. 65

steering knuckle. Reversed, 51. p59
Lever, Change-speed, 51. p6

Emergency-brake, 51i p6

Gear-shift, 51. p6

Spark, 51. p6

Speed-control, 51. p6

Throttle, 51. p6
Lifters, Valve, ^3, i>40
Lifting oil pumps, |10, pp76, 82
Limousine, 51. p35
Lines of force. Magnetic. 56. pl4
Live rear axle. Definition of. 51. PPl2. 71

rear axles. Plain, 51. p72
Livery automobile. 51. pl

car. 51. pl
Loads and air pressure for tires. 511. p24

and air pressure for tires. Table of. 51 1. p26
Lobes, Cam. 52. p5

Digitized by

Google

INDEX

XIX

Locking devices. Forau of quick-detachable.

(11, pl2
Lodestone. Definition of. |6. pl2
Lovtr-pressure lubrication tysteniis, (10, p65

speed. First, or. §9. p40

-tension coil. (6, p44

-tension contact igniter, |7. pi

-tension dual-ignition systems. (7. p46

-tension dual magneto system. (8. pl04

-tension magneto, (8. p29 •

-tension magneto. Construction of Splitdorf .
§8. pl04

-tension magneto dual ignition systems,
§8.p42

-tension magneto. Wiring diagram for Split-
dorf. (8. pl09

-tension single magneto system, (8, pp91, 92

-tension system of ignition. (7. ppl. 34
Lower, dead center. Outer, or. §2, p6
Lubricant, Definition of, §10. p43
Lubrication, Definition of. $10, p43

system. Pressure-feed, §10, p62

system. Splash, (10, p50

systems. Classification of engine, (10. p50

systems. Combined splash-and-pressure feed,
(10. p53

ssrstems. Examples of splash, (10, p53

systems. High-pressure, (10. p71

systems. Low-pressure, (10, pd5
Lugs. Tire, (11. pp4, 19

Magnet, Field, (8. p3
Magnetic circuit, (6, pl4

density, (6, pl4

field. (6, pl4

lines of force, (6, pl4

make-and-break igniter, (7. p4

neutral region. (6, pl3

poles. (6. pl3

screen. Movable, (8. p85

speedometer, (1, pp41, 44
Magnetism. Definition of. (6, pl2

Residual. (6. pl6; (8. pl2
Magnetite, Definition of. (6, pl2
Magnetizing, or excit^g coil. Definition of,
(6, pie

or magnetomotive force, (8, plO
Magneto armature core and winding. Construc-
tion of. (8. p24

armature shaft couplings, (8, p87

armature windings, (8, p28

Bosch single high-tension. (8. plOO

Construction of Bosch dual, (8. pllO

Construction of Eisemann dual, (8. pi 13

Construction of Ford high-frequency, (8, p92

Construction of Mea high-tension, (8, p95

Magneto, Construction of Splitdorf low-
tenskm, (8, pl04

Construction of two-point, (8, pl24

current. Graphic representation of. (8, p21

current. Interrupted primary, (8. p3d

current, Interrupted short circuit of primary,
(8,p40

current. Short-circuited primary, (8, p39

Definition of high-frequency alternating-cur-
rent, (8, p02

Definition of high-tension, (8, p46

dual ignition systems. Low-tension, (8, x>42

•dectric generators, (8, pi

field magnets, (8, p28

generator. Elementary, (8, p23

generator. Theory of, (8, pl9

ignition system. Definition of two-point,
(8, pl24

ignition systems, Classification of single,
(8,p91

Inductor type of, (8, p30

Low-tension, (8, p29

pole-piece construction. Special. (8. p87

Principle of operation of Mea. (8, p98

•shaft couplings, (9, p81

shaft. Methods of driving, (3, p45

spark range. Method giving spark variable
over, (8, p82

spark range. Methods giving spark uniform
over, (8, p83

system, High-tension dual, (8, pi 10

system. High-tension single. (8. pp91, 95

system. Low-tension dual. (8. pl04

system. Low-tension single, (8, pp91. 92

Wiring diagram for Ford, (8, p94

Wiring diagram for Mea, (8, p99

Wiring diagram for Splitdorf low- tension,
(8.P109

with double armature winding, High-ten-
sion. (8. p49

with single armature winding. High-tension,
(8.P46

with stationary armature. High-tension.
(8.P55

with stationary winding, High-tension. (8, pCO
Magnetomotive force. Magnetizing or, (8, plO
Magnetos, Classes of, (8, pi

Coil-type, (8, pi

Non-synchronous, (8, p2
Magnets and coils. Field, (8, p9

Definition of artificial, (6. pl2

Definition of permanent. (6, pl2

Magneto field, (8. p28

Natural. (6. pl2

Rocking field. (8. p83
Make-and-break igniter, Magnetic, (7, p4

-and-break system of ignition, (7, ppl, 34

Digitized by

Google

INDEX

Manifold. Outlet, f 2, p3
Manifolds, Exhaust, f3, p26

Inlet. i3. p24
Master vibrator. §6, p52
Materials for clutches, Friction, J9, p35

for plain bearings. (10, pl2
Mea high-tension magneto. Construction of,
^,p95

magneto, Principle of operation of, f8, p98

magneto, Wiring diagram for. (8, p99
Mechanically fastened tires, fll, pp3, 5

operated valve, §3, p37
Mechanism, Hand gear-shifting. f9, p48

Pneumatic gear-shifting, J9, p70

Sliding-shaft type of gear-shifting, $9, p50

Swinging-lever type of gear-shifting, J9, p52
Meter, Grade, §1, p41
Motor busses', Sl« pl

car, §1, pi

-generators, $6, p40

trucks, $1, pi

-vehicle wheels. Types of, |1, i>49

vehicles. Classification of, f 1, pi
Mounting front wheels, §1, p68
Movable magnetic screen, |8, p85
MudboU. §ll,p71

-guards, (1, p9

-hooks. (11, p43

-pan. Si. p8
Muffler cut-out valves, §4* Pp30, 33
Mufflers, Purpose and construction of exhaust,

54. p30
Multiple-ball coupling spark control, f8, p74

circuit. Parallel or, 56, plO

-disk clutches. Principle of, {9, pl4

or parallel, battery connections. $6, p26

•Bpring cone clutch. §9, p6

Natural magnets, $6, pl2

Negative terminal, or electrode, §6, plO

Neutral position, (9, p43

region. Magnetic. J6, pl3
New Departure double-row ball bearing,

(10. p38
No-cement tire patches, §11, p67
Non -adjustable ball-and-socket joint, (10, p9

-adjustable plain bearings, §10, p2

-parallelism of wheels, §11, p50

-poppet-valve engines, §2, pl3

-vibrator, induction coil. Transformer, or,
§6. p45
Norma roller bearing, §10, pl7
North pole, §6, pl3

Odometers, §1, i>40
Offset cylinders. §2, p29

Ohm, Relation of ampere, volt and, §6, p6
Ohm's law. §6, p7
Ofl, §10. p44

Clutches running in. §9, ppl6, 21

Cold test of. §10, p47

cups, §10, p88

Fire point, or test, of, §10, p47

Flash point, or test, of. §10, p47

gauge, Transferrmg, §10, p86

gauges. Glass,' §10, p85

-level gauge. Float, §10, pS5

-level gauges, §10, p85

pump, §2, p3

-pumps. Gear. §10. pp75, 77

ptmips, Lifting, §10, pp76, 82

relief valves, §10, p82

rings. Purpose of, §3, p33

sight-feed glasses, §10, p87

strainers, §10, p83
Oils, Properties of automobile-engine cylinder,
§10, p45

Viscosity of. §10. p47
Open, or broken, circuit, §6, plO
Operation of four-cycle engine, §2, plO

of three-port two-cycle engine, §2. pl7

of two-port two-cycle engine, §2, pl3
Order of explosions of four-cylinder four-cycle
engines, §2, p21

of explosions of six-cylinder engines, §2. p24

of explosions of two-cycle engines, §2. p46
Otto cycle, §2, p7

Outer, or lower, dead center, §2. p6
Outlet manifold. §2, p3
Outside casing protectors, §11, p70
Outward, stroke. Forward, or, §2, p6
Overflow, Radiator, §4, pl8
Oversize tires, §11, p22

Parallel, battery connections. Multiple, or,
§6, p26

battery. Reversed connections in, §6, p26

or multiple, circuit, §6, pll

-series battery connections, §6, p28
Patches, Cement tire, §11. p«5

Inner-shoe, §11, p69

Inside casing, §11, p69

No-cement tire, §11, p67
Pedal, Accelerator, §1. p6

Clutch, §1, p5

connections. Clutch-, §9, p30

Service-brake, §1, p6
Pedals, Adjustable clutch, §9, p31
Permanent magnets. Definition of, §6. pl2

tire treads. §ll.p23
Phaeton. §1. p33
Pin, Crank-, §2, p6

Digitized by

Google

INDEX

XXI

Pin, Piston, §2, p5

Pins. Mounting of piston, (3, p28

Piston pin, {2, p5

pins. Mounting of, ^, p28

rings, §3, p31
Pistons. Construction of engine. §3, p27
Plain live rear axles, fl, p72
Planetary change-speed gears, Principle of oper-
ation of, i/0, p58

transnussion. Two-speed, fO. p60

type of steering gear. 89. p96
Plants type of storage battery, §6, p32
Plugs, Examples of spark. $7, p5

Self-vulcanizing rubber and puncture,
§11. p67

Spark, §2, p6

Valve, §2, p6

with one coil. Two spark, 17. p42
Plunger force pumps, §10. pp76, 77
Pneumatic gear-shifting mechanism, 19, p70

tires. Types of. §11, pi
Polarization, Definition of, §6, p21
Pole. North. §6, pl3

-piece construction. Special magneto, §8, p87
Poles, Magnetic. §6. pl3
Poppet-valve engines, §2, pl3

valve springs. §3, p39

valves, §3. p37
Port. Exhaust. §2, p5

Inlet, §2. p5
Portable electric vulcanizer, §11, p74

gasoline vulcanizer, §11. p75

steam-heated vulcanizers. §11, p74
Position, Neutral, §9, p43
Positive terminal, or electrode. §6, plO
Potential, Definition of electric. §6, p4
Power plant, Unit, §1. pl4; §2. p42
Pressed-steel automobile frames, §1, pl06

-steel front axle. §1. p59
Pressure-feed lubrication system. §10, p52

gauges. Tire, §11, p39
Primary batteries. Definition of, §6, p21

coil, §6, p44

commutaiors. Timers, or, §7, plO

current. §6. p44

magneto current. Interrupted, §8, p36

magneto oirrent, Interrupted short circuit
of. §8. p40

magneto current. Short-circuited, §8, p39
Priming cups, Cylinder, §3, p48

valve. §2, p6
Progressive-gear quadrants. §9, p55

transmission. Definition of, §9, p38

transmission. Three-speed, §9. p44
Propelling the automobile. Methods of, §1. p9
Protectors, Detachable tire, §11, p40

Outside casing, §11, p70

Pump, Centrifugal water-circulating, §4. p20

ooimections to tire air valves, §11, p37

Diaphragm tire. §11, p32

Double-acting hand-operated tire, §11. p28

Gear water-circulating, §4, p22

Hand air. §1. p7

Methods of driving circulating. §3. p45

Oil, §2. p3

Single-acting hand-operated tire. §11. p27

Sliding-vane water-circulating, §4, p23

Water. §2. p3
Pumps. Application of engine-driven tire,
§11, p30

Classes of hand-oi>erated tire. §11, p27

fitted with guages. Tire, §11, p36

Gasoline air-pressure. §3. p48

Gear oil-. §10. pp75, 77

Lifting oil. §10. pp76, 82

Multiple-cylinder tire, §11, i)33

Plunger force, §10, pp76, 77

Single-cylinder engine-driven tire, §11, p30

Spark-plug tire, §11, p34
Puncture plugs. Self -vulcanizing rubber and,

§11. p67
Push rods. Valve. §2. p5

Quadrants. Progressive-gear, §9, p55

Selective-gear, §9, p54
Quick-detachable clincher tires. §11, pp3, 5
-detachable locking devices. Forms ■ of,

§ll.pl2
-detachable rim from wheel. Demounting,

§ll.p64
-detachable rims. Definitions of demountable

and, §U.p9
•detachable straight-side tires, §11, pp3. 7
-detachable tire tools, §11, p55
•detachable tires from rim. Removing,
§ll.p63

Raceabout, §l,p32

Racer, §1, p32

Radax ball bearings, §10, p37

Radial-and-thrust ball bearings, §10, p35

ball bearings, §10, p23
Radiator, §1, p8; §2, p3

construction. Cellular. §4, pl4

construction. Tubular, §4, plO

core. Definition of, §4, pU

overflow, drain, connections, and supports,
§4,pl8

Purpose of, §4, p2
Radiators, Honeycomb, §4, pl6

Types of, §4, p9
Radius rods, §1, ppl6. 93
Rating, Horsepower, §3, p50

Digitized by

Google

xxu

INDEX

Rear axle. Definition of dead, Si. ppl2, 71

axle. Definition of live. §1. ppl2, 71

-axle housings, §1, pS9

axle. Two-speed bevel-gear. |9. p72

axles. Example of dead, fl. p95

axles. Pull-floating, fl, p82

axles. Plain live. $1, p72

axles. Semifloating, fl. p76

axles. Three-quarter-floating, Si. p80

axles. Types of, §1, p71

axles, Worm-gear-driven, §1, p86

spring clips, %!, p72

wheels, §1. p9
Recharging of storage batteries when not in use,

S6. p38
Recoil clips. Spring, Sl> plOl
Rectifiers, Ccmverters. or. §6, p40
Regular clincher tires. §11, p3
Relief valves. Oil. $10. p82
Residual magnetism. $6, pl6; SS, pl2
Resistance and voltage of a cell, §6, pi I

Electrical. S^v p4

Internal. §6, pO
Return, or inward, stroke, §2. x)6
Reverse, Purpose of reversing gear, or, S9i p37

speed, S9, p42
Reversed cone clutches, §9. p9

connections in parallel battery, §6, p27

connections in series battery. ^, p20

Elliott steering knuckle, §1, pp57, 64

Lemoine steering knuckle, §1, p59
Reversing gear, or reverse. Purpose of, 59, p37
Rim, Bolted-on demountable, §11. plO

cutting. Tire. §11. p45

from wheel. Demounting quick-detachable,
§11, p64

Removing clincher casing from, §11, p69

Removing quick-detachable tires from,
§ll,p63
Rims. Care of. §11, p60

Circumfcrentially split, §11, pl6

Definitions of demountable and quick-
detachable, §11, p9

Transversely split, §11, pl3

Types of demountable, §11, p9
Ring type of universal joint. §9. p78
Rings, Piston, §3, p31

Purpose of oil. §3, p33
Road wheels. Front, §1, p6
Roadsters, §1. p32
Rocking field magnets, §8, p83
Rod, or bar. Torsion. §1. pl8

Yoke-and-eye. §10, p2
Rods and tubes. Torsion, §1, p91

Example of shifter, §9. p39

Radius, §1, ppl6, 93
Roller bearing. Bower. §10. pl8

Roller bearing Grant. §10. p22

bearing. High-duty Hyatt, §10, pl7

bearing. Norma, §10. pi 7

bearing. Standard, §10, p20

bearing, Timken. §10, p20

bearings. Straight. §10. pl5

bearings. Tapered, §10, p20

bearings. Types of, §10. pl4

chain, Baldwin detachable. §1. p97

type of universal joint, §9, p78
Rubber and ptmcture plugs. Self-vulcanizing,

§11. P67
Runabouts, §1, p31
Running boards, §1. p9

S. A. B. horsqwwer formula, A. L. A. M., or,

S3,pfiO
Scavenging, Cylinder. §2. p9
Screen. Movable magnetic, §8. p85
Screw-and-nut type of steering gear, §9, p92
Seat, Valve. §2. p6

Second, or intermediate, speed, §9, p40
Secondary coil, §6. i>44

commutators. Distributors, or, §7. pl2

current, §6, i>44

or storage batteries. Definition of. §6. p21

or storage, batteries, Examples of, §6. p30
Selective change-speed mechanism, Four-«peed,
§9,p47

-gear quadrants, §9, p54

transmission. Definition of, §9, p38

transmission. Vertical three-speed. §9. p39
Self-adjusting ball-and-socket joint. §10, plO

-curing cement. §11, p67

-excited, direct-current generator, §8, pl3

-excited dynamo-electric generators, §8, pll

-induction, §6, p41

-vulcanizing rubber and puncture plugs,
§ll.p67
Semifloating rear axles, §1, p7d
Semiracer, §1. p32
Series-battery connections, §6, p24

battery. Reversed connections in, §6, p26

-winding. Definition of. §8, pll

-wound dynamo-electric generators, §8, pll
Service brake, §9, p97

-brake pedal, §1, p6
Shackles. Spring, §1, p20
Shaft-drive driving-mechanism arrangements,
§1. Pl4

-driven automobile, §1, p9

Methods of driving magneto, §3, p45
Shields. Wind. §1, pp7, 38
Shifter forks. Example of. §9. p39

rods, Example of. §9, p39
Shock absorbers. Fluid. §1. plOS

Digitized by

Google

INDEX

xxm

Shock absorbers, Friction. |1, pl02

absorbers. Spring, §1, pl04

absorbers. Types of, 81, pl02
Shoe, Replacing tire, §11. p60

Tire casing, or. fll, p3
Short circuit of primary magneto current, In-
terrupted. (8, p40

-circuited primary magneto current. §8, p39
Shunt-wound dynamo-electric generator,

§8, pll
Shuttle-wound armature, §8, p28
Side-chain-drive car, §1, pl2

lamps. SI. p8
Sight-feed glass. (1, p8

-feed glasses. Oil. §10. p87
Signal horn, §1. p7
Single-acting engines, §2. pi

•chain-drive car, §1, pl2

high-tension magneto, Bosch, §8, plOO

magneto ignition systems, Classification of,
§8,p91

magneto system. High-tension. §8, pp91, 95

magneto system. Low-tension. §8. pp91. 92

-spark, high-tension ignition system, §7, p36

system. Wiring diagram for Bosch, §8, pl03

-tube tires, §11, pi
Six-cylinder engine with cylinders cast en bloc,
§2,p40

•cylinder engine with cylinders cast in pairs
and in threes. §2. p38

-cylinder engine with cylinders cast sep-
arately. §2. p36

•cylinder engines. Order of explosions of,
§2. p24

-cylinder four-cycle engine cylinders. Ar-
rangement of, §2, p23
Sizes. Designation of tire. §11. p21
Sliding change-speed gears. Classification of,
§9.p38

-shaft type of gear-shifting mechanism,
§9.p50

•vane water-circulating pump. §4, p23
Slip cover. Automobile top, §1, pp9, 37

sleeve of universal joint, §9. p76
Sod pan, §l.p9
Solenoid. Properties of, §6, pl7
Solid front axles, §1, p57

tires. §11. pi
Space, Compression, §2, p6
Spark coil, §1. p7

control, §1, p6

control, Atwater-Kent automatic, §8. p75

-control construction. Example of hand,
§8.p66

control. Eisemann automatic, §8. p69

control, Franklin governor. §8. p71

control. Multiple-ball coupling. §8, p74

Spark control. Operation of hand. §8, p65

control. Principle of operation of governor,
§8. p68

Fixed, §8, pp64, 78

gap. Auxiliary, §7, p9

generator, Atwater-Kent, §7, pi 6

intensity. Factors affecting. §8, p79

intensity on starting engine. Influence of,
§8,p81

lever. §1. x)6

Methods of producing electric. §8. p03

Methods of starting on the, §8, p89

-plug tire pumps, §11, p34

plugs. §2. X)6

plugs. Examples of. §7, p5

plugs with one coil. Two. §7. iA2

range. Methods giving spark uniform over
magneto, §8. p83

range. Method giving spark variable over
magneto, §8. p82

Requirements of starting on the. §8. p89

-time control. Methods of. §8, p64

-time variation. §8, p64
Speed-change gea: — -nd clutch. Interlocking
device for, §9. p&/

-control lever. §1, p6

First, or low, §9, p40

Reverse, §9, p42

Second, or intermediate, §9. p40

Third, or high, §9. pll
Speedometer. §1, p8

Centrifugal, §1, pp41. 42

Definition of, §1, p40

flexible- joint drive, §1, p47

Magnetic, §1, pp41, 44

temperature-compensating device, §1, i>45
Speedometers, Classes of. §1. p41

Electric, §1. p42

Fluid-pressure. §1, p42
Splash and pressure-feed lubrication system.
Example of combined. §10. p73

-and-pressure feed lubrication systems. Com-
bined. §10. p53

lubrication systeip. §10, p50

lubrication systems. Examples of, §10, p53
Splicing inner tubes. §11, p68
Split rims, Circumferentially, §11, pl5

rims. Transversely, §11, pl3
Splitdorf dual system of ignition. Principle of
operation of, §8, pi 05

low-tension magneto. Construction of,
§8. pl04

low-tension magneto. Wiring diagram for,
§8. pl09
Spring automobile wheels. §1, p55

clips. Rear, §1, p72

recoil clips, §1, plOl

Digitized by

Google

XXIV

INDEX

Spring thaddet, fl, p20

■hock atowotben, fl. pl04
Springs. Conatnaction and typei of automobile,
I1.P98

Poppet vahre, f3, p39

Undenlung. |1, p61

Valve. S2. p3
Spur-gear differential, il, p76; fO, p84
Standard roller bearing. flO. p20
Starter air-snessure gauge. §1, p7
Starting crank, §1, p8

engine. Influence of q>ark inteotity on,
I8.P81

on the fpark. Methods of, |8. p89

on the spark, Requirements of. |8. p80
Steam-heated vulcanizer, Portable, fll. p74
Steering column, il, p5

connections, il, p66

connections. Arrangement of. i9. p86

gear. Bevel-pinion-and-aector. iO. p95

gear. Planetary type of. i9, p96

gear. Screw-and-nut type of. iO. p92

gear. Worm-and-sector. i9. p91

gear. Worm-«nd-worm-wheel. i9, p89

gears, Classification of, i9. p88

knuckle. Elliott, il. pp57, 62

knuckle. Lemoine, il. pp57. 65

knuckle. Reversed EllioU. il. pp67. 64

knuckle. Reversed lemoine. il. i>60

knuckles, Definition of. il, p61

Methods of caster, il. p69

wheel, il. p5
Stock. Cushion, ill. p80

Tread, ill. p78
Stone bruises. Tire, ill. p52
Storage batteries. Capacity of, i6. p34

batteries, Charging of. i6. p34

batteries. Definition of secondary, or, i6. p21

batteries. Examples of secondary, or, i6. p30

batteries when not in use. Recharging of,
i6.p38

battery. Faur6 type of, i6. p32

battery floated on the line. i8. pl6

battery. Laying up. i6. pd9

battery. Plant* type of, i6. p32

Preservation of tires in. ill. p52

tanks. Tire inflation from. ill. x>36
Storm front, il. p38
Straight-side tires. Quick-detachable,

ill. pp3. 7
Strainers. Oil. ilO. p83
Strips, Breaker, ill. p4
Stroke. Compression. i2. pl2

Exhaust. i2. pl3

Forward, or outward. i2. p6

Return, or inward. i2. p6

Suction. i3. plO

Stroke, Working, i2, pU
Subframes. il, pl06
Suctkm stroke, i2. plO
Sun-and-planet motion. i9, p58
Supports. Radiator. i4. pl8
Suspension automobile wheels, il. p40

Four-point engine. i2. p44

Three-point engine, i2, pp29, 44
Swinging-lever type of gear shifting medianism,

i9.p62
Switch. Double-throw, two-pole, blade. i7, p26

Single-throw, two-pole, knife, or blade.
i7.p25
Switches. Battery. i7, p21
Swivel bearings. ilO. p7
Ssmchronous operation. i7. pll

T-head type of engine cylinder, i3, pi

Table of freesing point of antifreezing mixtures
of calcium chloride and water. i4. p%
of freeing point of antifreezing mixtures of

wood alc<^ol and water. i4. p25
of horsepower by A. L. A. M. formula.

i3.p52
of load and air presstare for tires, ill, p26

Tables of identification numbers of ball bear-
ings. ilO. p30

Tail-lamp. il. p8 -

Tapered roller bearings. ilO. p20

Taxicab body. il. p36

Taxicabs. il. pi

Temperature-compensating device. Speed-
ometer, il, i>45

Terminal, or electrode, Negative, i6. plO
or electrode. Positive. i6. plO

Terminals. Definition of, i6, plO
Wire. i7. p27

Theory of magneto generator. iS, pl9

Thermo-siphon cooling systems. i4, p5

Third, or high, speed. i9. i>41

Three-cylinder two-cycle engine. Example of,
i2. p51
•plate clutch. i9. pl9
-point ball bearings. ilO, p35
-point engine suq>enJuon. i2. pp29. 44
-port two-cycle engine. Operation of. i2. pl7
•<luarter-floating rear axles, il. p80
-speed progressive transmisson. i9. p44
-speed selective tranamisncm, Vertical,
i9. p39

Throttle, Foot-, il, p6
lever, il. p6

Thrust bearings. Ball. ilO. p39
bearings, Plain, ilO, pll

Timer and distributor, combined, i7, pl6
Example of four-point, i7, p44

Digitized by

Google

INDEX

XXV

Timers, or primary oommutaton, 17, plO
Ttmken roller bearing, flO, p20
Tire air valves, §11, pl6

air valves. Pump connections to, $11, p37

blisters, {11, p50

casing, or shoe, §11, p3

casings. Vulcanizing, §11, p77

chains. §11, p42

chains. Improperly fitted. §11, p60

cuts and blisters. Repair of, §11, p71

Detachable-tread. §11. p7

detaching tools, §11. p54

Dtmlop, §11. pp3, 7

fabric. Pulling loose of. §11, p49

failure. Causes of. §11. i>45

fork. §11, p56

inflation from storage taxiks, §11, p30

innerlinera, §11, p41

irons. §11, i>53

lugs. §11. pp4. 19

patches. Cement. §11. p65

patches. No-cement. §11. p67

pressure gauges. §11. p39

protectors. Detachable. §11. p40

pump. EHaphragm. §11. p32

pump, Double-acting hand-operated, §ll.p28

pump, Single-acting, hand-operated, §11. p27

pumps, Application of engine-driven, §1 1 , p30

pumps, Classes of hand-operated. §11. p27

pumps fitted with gauges. §11. p36

pumps. Multiple-cylinder. §11. p33

pumps. Single-cylinder engine-driven, §11, p30

pumps. Spark-plug, §11, p34

rim cutting, §11. p45

shoe. Replacing, §11. i)60

sizes. Designation of, §11, p21 *

Soft. §11. p24

stone bruises. §11, p52

tools. Quick-detachable. §11, p55

tread. §11. p4

treads. Permanent, §11, p23

wear. Additional causes of undue, §11. p62

wear due to improper driving, §11. p49
Tires. Classification of double-tube, §11, p2

Cushion, §11, pi

from rim, Removing quick-detachable.
§ll.p63

in storage. Preservation of, §11. p52

Loads and air pressure for, §11, p24

Mechanically fastened, §11, pp3, 5

Methods of inflating, §11, p25

Oversize, §11, p22

Quick-detachable clincher, §11. pi>3. 5

Quick-detachable straight-side. §11. pp3, 7

Regular clincher, §11, p3

Single-tube. §11. pi

Solid. §11, pi

222B— 64

Tires, Table of loads and air pressure for,
§11. P26

Tyx>es of pneumatic, §11. pi

Under-inflation of, §11, p45
Toe board, §1. p5
Toggle expanding brake, §9, p99
Tools, Qtiick-detachable tire, §11, p55

Tire detaching. §11. p54
Top. Folding. §1, p9

slip cover. Automobile, §1, pp9, 37
Tops, Canopy automobile, §1, p37

Cape automobile, §1, p37
Torsion rod, or bar. §1. pl8

rods and tubes. §1. p91

tube. §1. pl6
Touch-spark system of ignition. §7. ppl, 34
Touring cars. §1. p33

coach body. §1, p36
Train. Bpicyclic-gear, §9, p58
Transformer, or non-vibrator, induction coil,

§6, p45
Transmission brake. §9, pl03

Definition of horizontal. §9, p38

Definition of progressive, §9, p38

Definition of selective, §9, p38

Definition of /ertical. §9, p38

Friction-gear, §9, p62

Purpose of change-speed gears, or. §9. p37

Three-speed progressive, §9, p44

Two-speed planetary, §9, p60

Vertical three-speed selective, §9, p39
Transferring oil gauge, §10. p86
Transversely split rims, §11. pl3
Tread band. §11. p79

Hand-wrapped, §11, p80

Molded, §11. p80

stock. §11. p78

Tire, §11. p4
Treads, Permanent tire. §11, p23
Trembler, or ctirrent interrupter. Vibrator,

§6,p49
Trucks, Auto, §1, pi
Tube. Chafing of inner. §11, i>49

Inner, §11. p3

Inserting an inner, §11. p61

Removing inner, §11. p56

Torsion, §1, pld
Tubes, Carrying inner, §11, p72

Pinching inner, §11, p62

Splicing inner. §11, p68

Torsion rods and, §1, p91

Vulcanizing inner, §11, p75
Tubular front axles, §1, p59

-radiator construction, §4, plO
Twin cylinders. §2, p20

Two-cycle engine cylinders, Ammgement of,
§2,p46

Digitized by

Google

XXVI

INDEX

Two-cycle engine. Definition of, |2. p8
-cycle engine. Example of three-cylinder,

12. p51
-cycle engine. Example of two-cylinder,

§2.p4S
•cycle engine. Operation of three-port. $2, pi 7
-cycle engine. Operation of two-port, 12. pl3
-cycle engine, Valveless. $2, pl7
-cycle engines. Order of explosions of, 12, p46
-cycle principle. Application of, $2. p48
-cylinder-engine ignition. §7, p43
-cylinder four-cycle engine cylinders, Ar-
rangement of, (2, pl9
-cylinder two-cycle engine. Example of,

§2.p48
-point ignition system. Wiring diagram for,

|8. pl25
-point magneto. Construction of. (8, pl24
-point magneto ignition system. Definition

of. |8. pl24
-port two-cycle engine. Operation of, |2. pl3
-speed bevel-gear rear axle, SO. p72
-speed planetary transmission, (9, p60
Typical crank-cases. |3, pl6

Under-inflation of tires, §11, i>45
Underslung frames, §1, pl07

springs. §1. pdl
Unit power plant. §1. pl4; §2, p42
Universal joint, fl, pl6

joint. Block-and-trunnion tirpe of, 19, p78

joint. Cross type of, §9. p76

joint. Ring type of, §9. p78

joint. Roller type of. §9, p78

joint. Slip sleeve of. §9, p76
Upper, dead center. Inner, or, 12, p6

Valve, Automatic inlet, §3, p37
cam-lever. §3, p44
cam-shaft. Example of. |3. p40
cam-shaft. Methods of driving, f3, p45
cam-shafts. §2. p.'S
cams. §2. p5

cams. Examples of, |3, p40
Exhaust. |2. p5

-in-the-head t3rpe of engine cylinder, §3, jA.
Inlet. S2, p5
lifters. §3, p40

Mechanically operated, §3, i>37
plugsv §2. p6
Poppet, §3, p37
Priming. §2. p6
push rods. §2, p6
seat, 12, p5
springs, (2, p3

Valve springs. Poppet. (3. p89
Valveless two-cycle engine, 12, pl7
Valves in cylinder head, (3. p45

Muffler cut-out, |4. PI>30. 33

Oil relief, flO. p82

Pump connections to tire air. §11, i>37

Tire air, |11. pl6
Variation. Spark-time, §8. p64
Vehicles. Classification of motor. |1, pi

Commercial. |1, pi
Vertical engines. §2. p7

three-speed selective transmission, §9, p39

transmission. Definition of. §9, p38
Vibrator impact device. §6, p49

induction coil. Example of, §6, i>47

Master, §6. p52

trembler, or current interrupter, §6, p49
Viscosimeter, |10, p47
Viscosity of oils. §10. p47
Volt, and ohm. Relation of ampere, §6, pa

Definition of. §6, p5
Voltage of a cell. Resistance and. §6, pll
Voltaic cell. Construction of. §6, p9
Voltammeter connections, §7, p33
Voltammeteis. §7. p28

Hoyt. §7. p30
Voltmeter. Definition of, §6, p5: §7. p28
Vulcanisation, Definition of. §11, p73
Vulcaniser. Portable electric. §11, p74

Portable gasoline, §11. p75

Portable steam-heated, §11, p74
Vulcanizing inner tubes, §11, p76

tire casings. §11, p77

Wagolk, Delivery. §1, pi
Water-circulating ptunp. Centrifugal. §4. p20
•circulating pump. Gear, §4, p22
-circulating pump. Sliding-vane. §4, p23
-jacketed cjrlinders with integral heads and

jackets, §3, pi
-jacketed cylinders with 8q>arate heads.

§3,p7
-jacketed cylinders with separate water-
jackets, §3, plO
pump, §2. p3
Wear, Additional causes of undue tire,

§11. P52
Wet batteries. Definition of. §6. p21

cells. Uses of. §6, p22
Wheel. Demotmting quick'detachable rim froin»
§ll.p64
Steering. §1. p5
Wheels. Artillery automobile, §1. i>49
Compression automobile, §1, i>49
Dished automobile. §1, p50
Front road, §1, p5

Digitized by

Google

INDEX

xxvu

Wheels, Mounting front, §1, p68

Non-parallelism of, §11. p50

Rear. (1, p9

Spring automobile, fl. p55

Suspension automobile. {1. p49

Types of motor-vehicle, Jl, p49

Wire automobile, §1. p52

Wooden automobile, §1. p49
Wind shields, 51. pp7, 38
Winding. Corstruction of magneto annatxire
core and. (8, p24

Definition of compound field. §8, pl2

Magneto armature. §8, p28
Wipe-spark system of ignition, $7, pp] , 34
Wire automobile wheels. §1, p52

terminals. 17, p27
Wires. Insulated, §7. p26
Wiring diagram for Bosch double ignition sys-
tem. (8. pl21

diagram for Bosch dual system, |8. pill

diagram for Bosch single system, §8. pl03

Wiring diagram for Eisemann dual system.
{8. pi 15

diagram for Ford magneto. §8, p94

diagram for Mea magneto. §8, p99

diagram for Splitdorf low- tension magneto.
§8. pl09

diagram for two-point ignition system,

■ S8. pl25
Wooden automobile frames, §1, pl05

automobile wheels, $1, p49
Working stroke, §2, pl2
Worm-and-sector steering gear, §9, p91

-and-worm-whcel steering gear, §9, p89

-bevel drive, §9, p8.5

-gear-driven rear axles, §1, p(86

Yoke-and-eye rod, §10, p2
end. Adjustable, §10, p3
end. Plain, §10, p2
of electromagnet, §6. pl8

Digitized by

Google

Digitized by

Google

Digitized by

Google

1G8 ^ Wi

Digitized by

Google

J^'- Digitized by VjOOQIC

Digitized by

Google

Internet Archive Audio

Featured

Top

Images

Featured

Top

Software

Featured

Top

Texts

Featured

Top

Video

Featured

Top

Mobile Apps

Browser Extensions

Archive-It Subscription

Save Page Now

Full text of "Gasoline automobiles ; Gasoline automobile engines ; Automobile engine auxiliaries ; Electric ignition ; Transmission and control mechanism ; Bearings and lubrication ; Automobile tires"

See other formats